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Human Molecular Genetics Advance Access originally published online on May 11, 2005
Human Molecular Genetics 2005 14(13):1753-1762; doi:10.1093/hmg/ddi182
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© The Author 2005. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oupjournals.org

Genomic architecture of human 17q21 linked to frontotemporal dementia uncovers a highly homologous family of low-copy repeats in the tau region

Marc Cruts{dagger}, Rosa Rademakers{dagger}, Ilse Gijselinck, Julie van der Zee, Bart Dermaut, Tim de Pooter, Peter de Rijk, Jurgen Del-Favero and Christine van Broeckhoven*

Department of Molecular Genetics, Flanders Interuniversity Institute for Biotechnology, University of Antwerp, Antwerpen, Belgium

* To whom correspondence should be addressed at: Department of Molecular Genetics, Neurodegenerative Brain Diseases Group, University of Antwerp—Campus Drie Eiken, Universiteitsplein 1, B-2610 Antwerpen, Belgium. Tel: +32 38202601; Fax: +32 38202541; Email: christine.vanbroeckhoven{at}ua.ac.be

Received April 14, 2005; Accepted May 3, 2005


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 RESULTS
 DISCUSSION
 MATERIALS AND METHODS
 REFERENCES
 
Familial frontotemporal dementia (FTD), characterized by tau-negative, ubiquitin-positive inclusions at autopsy, is linked to a chromosomal region at 17q21 (FTDU-17), encompassing the gene encoding the microtubule associated protein tau, MAPT. Mutations in MAPT were previously identified in familial FTD with parkinsonism (FTDP-17); however, in FTDU-17 patients, no pathogenic mutations were found in exonic regions consistent with the lack of tauopathy in FTDU-17 brains. Here, we excluded mutations in MAPT by genomic sequencing of 138.5 kb in FTDU-17 patients. Next, to facilitate the identification of the actual underlying genetic defect, we assembled the 6.5 Mb FTDU-17 sequence. Annotation demonstrated that MAPT is surrounded by three highly homologous low-copy repeats (LCRs) in a region of 1.7 Mb. Using evolutionary studies, short tandem repeat-based linkage disequilibrium (LD) and macro-restriction mapping, we demonstrated that these LCRs are at the basis of a series of rearrangements in the MAPT genomic region. One is an inversion that occurred 3 million years ago and resulted in a common polymorphism in humans to date. This inversion plus flanking LCRs spanned ~1.3 Mb and was shown to underlie the extended LD and haplotypes H1 and H2 across MAPT. However, in the FTDU-17 families, we ascertained segregation analysis precluding a relationship between the FTDU-17 and the H1/H2 inversion. The presence of multiple homologous LCRs in the region predicts that other potentially more complex genomic rearrangements might be underlying FTDU-17.


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
RESULTS
 DISCUSSION
 MATERIALS AND METHODS
 REFERENCES
 
Frontotemporal dementia (FTD, OMIM 600274 [OMIM] ) is the second most frequent type of neurodegenerative dementia clinically characterized by initial behavioral and psychological disturbances, followed by cognitive decline eventually leading to dementia. FTD is an etiologically complex disorder with genetic components contributing to disease. In 20% of patients, FTD is compatible with autosomal dominant inheritance (1Go). In 10–43% of families with FTD and parkinsonism linked to 17q21 (FTDP-17), mutations were identified in the gene encoding the microtubule associated protein tau (MAPT, OMIM 157140 [OMIM] ) (FTD Mutation Database http://www.molgen.ua.ac.be/FTDMutations) (2Go). FTDP-17 patients with MAPT mutations are neuropathologically characterized by intracellular inclusions of tau deposits (tauopathy).

In 33% of FTD patients, ubiquitin-staining inclusions (FTDU) are observed in the absence of tauopathy (1Go). A number of autosomal dominant FTDU families were linked to regions at chromosome 17q21 encompassing MAPT (FTDU-17) (2Go). So far, extensive mutation analyses of MAPT exons and flanking intronic sequences did not identify pathogenic mutations. In one extended Dutch FTDU-17 family, family 1083, we were able to significantly refine the linkage interval to 4.8 cM between D17S1787 and D17S958 (3Go). In addition to MAPT exonic mutations, we excluded pathogenic mutations in the saitohin gene (STH) located within intron 9 (3Go) and in the presenilin homolog 2 (PSH2, IMP5) located just upstream of MAPT (4Go).

The MAPT genomic region was recently shown to be genetically complex, characterized by the presence of an inversion that is common in the population (5Go). This inversion results in high linkage disequilibrium (LD) in a region of 1.3 Mb across MAPT (6Go–8Go), producing two extended LD haplotypes that were previously designated H1 and H2 (9Go). H1 has been consistently associated with increased risk for sporadic tauopathies like progressive supranuclear palsy and cortical basal degeneration worldwide (2Go). We recently analyzed the H1-based allelic heterogeneity of MAPT by sequencing of 138.5 kb genomic sequence (R. Rademakers et al., unpublished data). We identified 153 H1 genetic variants and used these to examine the LD substructure within MAPT on the basis of which we selected 15 haplotype-tagging SNPs capturing >90% of MAPT haplotype diversity. Here, we extended the genetic analyses of MAPT by examining the 138.5 kb genomic sequence, including upstream and downstream conserved regulatory regions for pathogenic mutations in FTDU-17 patients. Further, we constructed and annotated the 6.53 Mb genomic sequence contig of the FTDU-17 region. We provided evidence for the presence of three highly homologous low-copy repeats (LCRs) surrounding MAPT and studied their genomic organization, their relationship to the MAPT H1/H2 inversion and their impact on genomic evolution.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 RESULTS
DISCUSSION
 MATERIALS AND METHODS
 REFERENCES
 
MAPT genomic sequencing
We determined 138.5 kb MAPT genomic sequence including 3.9 kb upstream and 3.7 kb downstream sequences conserved in rodents, in three patients and two non-segregating at risk relatives of FTDU-17 family 1083 and in 18 unrelated individuals. We did not include stretches of interspersed repeat sequences (35.26% as identified by RepeatMasker, http://www.repeatmasker.org) and obtained 96 kb sequence of which 81 kb unique sequence in each individual. In family 1083, FTDU-17 segregated with H1 (3Go); two patients used in sequencing were H1/H1, whereas one was H1/H2 for the MAPT haplotypes. In total, we identified 574 sequence variants, including 424 variants differentiating H1 from H2 (H2 variants). One variant, g.38276T>A (numbering relative to AC091628 [GenBank] .2) located in MAPT intron 0, was present only in FTDU-17 patients of family 1083. Genotyping this SNP in 189 unrelated Dutch control individuals demonstrated that the A-allele was heterozygous in 57 and homozygous in 10 control individuals, resulting in a minor allele frequency of 20.4%.

Assembly and annotation of the FTDU-17 genomic sequence
We assembled the genomic DNA sequence of the FTDU-17 region between D17S1787 and D17S958 (3Go) on the basis of public finished and unfinished draft sequences of the human genome, and obtained a single contiguous sequence sized 6.53 Mb. Later, NCBI Build 35 of the human genome (hg17) confirmed our assembly efforts. The region contained 145 known genes based on the ‘Known Genes’ track of the UCSC human genome browser. Complete annotation of the 300 kb segment between DRF1 and CRF based on sequence homologies with human and non-human genes and spliced ESTs, gene predictions and conserved elements demonstrated that this region contained five novel unknown genes, in addition to seven known genes represented by Refseq sequences. The density of known genes in this region and the FTDU-17 region is highly comparable (one known gene per 45 kb) and extrapolation of the ratio of known genes to novel genes suggested that the total number of genes in the FTDU-17 region might be about 249, resulting in a gene density of one gene per 26 kb.

LCRs in the MAPT genomic region
While assembling the sequence contig of the FTDU-17 region, different fragments of the same unfinished draft sequences entered into the contig at two locations 250 kb centromeric and 200 kb telomeric of MAPT, respectively. Also, retrieval of sequences homologous to these regions resulted in a much higher number (N=88) of genomic sequences when compared with other regions. These observations suggested that MAPT is flanked by duplicated sequences. To examine this possibility, we analyzed ~2 Mb genomic sequence surrounding MAPT (further referred to as MAPT genomic region) suspected of containing repeated homologous segments. In this region, we identified three LCRs with >97% local similarity within a 1.7 Mb sequence (Fig. 1). One LCR sized 227 kb, LCR A, was located 250 kb centromeric of MAPT, whereas the other two LCRs, LCR B (sized 503 kb) and LCR C (sized 123 kb), were located, respectively, at 180 and 950 kb telomeric of MAPT and were inverted relative to LCR A. The LCRs were composed of three (LCR C) to nine (LCR B) occurrences of eight different subunits (Fig. 2). In LCR A, a 4 kb sequence in subunit 2 was repeated in tandem (Fig. 2). In LCR B, a duplication of subunits 2 and 8 (together 237 kb) was detected, of which subunit 8 (182 kb) was present in LCR B only (Fig. 2). LCRs A and B were interrupted by stretches of unique sequence: in LCR A, subunits 3 and 4 were separated by 17 kb unique sequence, whereas in LCR B, 98 kb unique sequence was localized between subunits 5 and 6 and 41 kb between subunits 4 and 7. Maximal local similarity between LCRs was observed in LCR subunit 2 and ranged from 97.4% over 8.0 kb (LCR A versus LCR C) to 99.2% over 12.0 kb (LCR A versus LCR B). LCRs A and B were most homologous with 40.6 kb having a sequence identity ≥90%.



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  		Figure 1. Sequence annotation of the MAPT genomic region containing LCRs A–C at 17q21 and the LCR D region at 17q24.1. (A) Dot plot comparison of the 17q21 region ranging from AC003070 [GenBank] to AC002558 [GenBank] with itself (triangle) and with the LCR D region ranging from AC009994 [GenBank] to AC037487 [GenBank] (rotated rectangle). Dot plot colors reflect degree of sequence identity. Colored arrows below dot plots represent LCR components. (B) Clone contig showing location of genes outside the LCRs and STR markers. Detailed annotation of LCRs A–C is shown in Figure 2. Black arrows indicate large-insert clones labeled with GenBank accession number. Red arrows represent genes. Single-copy STR markers are shown in green; multiallelic STR markers in pink. FMNL1: formin-like 1; MAP3K14: mitogen-activated protein kinase kinase kinase 14; ARHGAP27: Rho GTPase activating protein 27; CRHR1: corticotropin releasing hormone receptor 1; IMP5: intramembrane protease 5; STH: Saitohin; NSF: N-ethylmaleimide-sensitive factor; WNT3: wingless-type MMTV integration site family, member 3; WNT9B: wingless-type MMTV integration site family, member 9B; GOSR2: golgi SNAP receptor complex member 2; CDC27: cell division cycle 27 dependent kinase 27; DDX5: DEAD (Asp-Glu-Ala-Asp) box polypeptide 5; SMURF2: SMAD-specific E3 ubiquitin protein ligase 2 and GNA13: guanine nucleotide binding protein (G protein) alpha 13.

 


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  		Figure 2. Detailed structure of MAPT LCRs. All LCRs are drawn from centromere (left) to telomere (right). (A) LCR A. Red open boxes represent a 4 kb tandem duplication (B) LCR B, (C) LCR C and (D) LCR D. Colored arrows indicate paralogous sequences. Rectangles, representing paralogous exon sequences, are color-coded based on the gene from which they derive. Rectangles connected with a horizontal line represent transcribed sequences (Table 2). PLEKHM1: pleckstrin homology domain containing, family M member 1; NBR2: neighbor of BRCA1 gene 2 and ARF4L: ADP-ribosylation factor 4-like.

 
Not all LCR-containing sequences assembled into the contig and seven additional contigs were generated indicating that additional related LCRs existed in the human genome. All LCRs localized to 17q in a 38 Mb region ranging from 17q11.2 to 17q24.2 (Table 1). The sequence of the LCR located at 17q24.1 was highly homologous to LCR A over a 154 kb region (subunits 1–3) and therefore represented another member of the same LCR family (LCR D). LCR D is oriented in the same direction as LCR A (Fig. 1) and was composed of four subunits (Fig. 2). Highest sequence similarity was with LCR A, i.e. 98.1% over a 13.3 kb region in subunit 2. Together, LCRs A–D represent members of the MAPT LCR family. The six remaining LCRs were composed mainly of elements of other chromosome 17 LCR families, though interspersed with sequences of the MAPT LCR family. In addition, short stretches of MAPT LCR sequences are distributed across the entire 17q arm.


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  		Table 1. Distribution of LCRs homologous to MAPT LCRs A–C sequences
 
Gene annotation of the MAPT genomic region identified four known genes located between LCRs A and B, CRHR1, IMP5, MAPT and STH, in addition to putative genes, FLJ25168, BC018035 [GenBank] and LOC284058 (Fig. 1). Three genes were located between LCRs B and C: WNT3, WNT9B and GOSR. Six genes were entirely embedded within LCR sequences: LOC201175, PLEKHM1, NBR2/ARF4L, KIAA0563/LOC9894, BC066350 [GenBank] and LOC401884 (Table 2 and Fig. 2). All except BC066350 were present in LCR A and all except BC066350 and LOC401884 in LCR D, and are likely transcriptionally active since LCR-specific ESTs were identified (Table 2). Paralogous sequences are variably present in LCR B and LCR C (Table 2, and Fig. 2). Two genes were transcribed from within LCR sequences: ARHGAP27 is transcribed from telomere to centromere with exon 1 located in LCR A; NSF is transcribed from centromere to telomere with exons 1–13 located in the duplicated subunit 8 unique to LCR B. In LCR B, we identified multiple ESTs containing LOC401884 and exon 2 of LOC284058 suggesting that in LCR B, the paralogous sequences of LOC401884 represent alternative 5' exons of LOC284058 (Fig. 2).


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  		Table 2. Genes located inside the MAPT LCRs
 
Synteny mapping
We compared the MAPT genomic region in human with that of mouse at chromosome 11qE1 (Fig. 3). Mice had only one orthologous copy of AF258593, PLEKHM1, KIAA0563/LOC9894, NBR2/ARF4L and LOC401884, localized telomeric of Map3k14 comparable to the position of LCR A in humans, suggesting that LCR A is the ancestral sequence from which the human MAPT LCRs B–D originated by segmental duplication. Also, duplicated subunit 8, unique to LCR B and containing exons 1–13 of NSF, was present only once in mouse. Further, the gene order in mice differed such that Gosr, Wnt9b, Wnt3 and Nsf appeared first and in reversed order before Crhr1, Imp5, Mapt and Sth. Also, synteny was interrupted at each of the three human LCRs (Fig. 3).



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  		Figure 3. Synteny map of the human and mouse MAPT genomic region. (A) Dot plot comparing human (x-axis) and mouse (y-axis) genomic sequence. Colored arrows represent syntenic segments, black arrows represent genes and gray arrows represent human LCRs. (B) Sequence of evolutionary inversion events explaining difference in gene order between human and mouse.

 
In chimpanzee (Pan troglodytes), the gene order in the syntenic region on chromosome 19, was identical to human between MAP3K14 and MAPT including the genes in LCR A. The order of genes between LCR B and LCR D was reversed in the chimpanzee syntenic sequence. However, the chimpanzee sequence had gaps at the sites where LCR B and LCR D reside in humans preventing a fixed orientation of these sequence scaffolds. Nevertheless, we detected multiple regions in chimpanzee chromosome 19 that were homologous to the human LCRs A–D, suggesting that multiple copies were also present in the chimpanzee genome. Together, these data can be explained by at least two inversions of the genomic segments between the LCRs in human when compared with mouse (Fig. 3), at least some of which must have occurred before chimpanzee speciation.

Extended LD in the MAPT genomic region
To determine the extent of the H1 and H2 haplotypes, we analyzed 18 short tandem repeat (STR) markers located in the MAPT genomic region (Fig. 1B) in 23 nuclear families. Seven STRs displayed more than two alleles per individual: four recognized sequences in LCRs A, B and D and three in the tandem duplicated sequence unique to LCR B. The observation that sequences in these LCRs PCR amplify using the same primers illustrated the limited sequence divergence between and in the LCRs. We performed segregation analysis of the 11 remaining STRs and MAPT haplotypes H1 and H2 defined by MAPT SNP16 to determine 17q21 haplotypes. Four STR markers located between LCR A and LCR B showed a dichotomous distribution of H1- and H2-specific alleles: two STRs flanking MAPT (chr17-44 and chr17-20) and two within MAPT (chr17-19 and chr17-28). Distortions of H1 and H2 allelic distributions were also observed for two more centromeric STR markers (D17S810 and chr17-18). Association analysis showed highly significant (P<0.005) allelic association for these six STR markers and significant association (P<0.05) for chr17-16 centromeric and D17S920 telomeric of MAPT (Table 3), coinciding with the 1.33 Mb region ranging from LCR A to LCR B. This evidenced that the non-allelic homologous recombination that resulted in the inversion defining the extended H1 and H2 haplotypes must have occurred between LCR A and LCR B.


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  		Table 3. Association analysis of chromosome 17q21 STRs with MAPT H1/H2 haplotypes
 
Pulsed-field gel electrophoresis analysis
To localize the H1/H2 inversion breakpoints, we performed pulsed-field gel electrophoresis (PFGE) restriction mapping of NotI-digested genomic DNA of different H1/H2 genotype carriers using single-copy hybridization probes flanking each of LCR A, MAPT and LCR B at the centromeric (cen) and telomeric (tel) side (Fig. 4). Each probe hybridized multiple fragments with variable intensity suggesting that the NotI restriction digestion was partially inhibited by DNA-methylation. When comparing hybridization signals of H1 and H2 chromosomes, we observed no fragment size differences for the probes MAPTcen, MAPTtel, LCRAtel and LCRBcen, located between the LCRs. Hybridizing with LCRAcen, resulted in H2 fragments that were ~70 kb longer than the H1 fragments. Hybridizing with LCRBtel, resulted in an H2 fragment that was ~98 kb longer than the H1 fragment. In addition, a constant fragment of 120 kb was observed for both haplotypes resulting from the location of LCRBtel in subunit 8, duplicated in LCR B (Fig. 4A). When performing the same hybridization experiments using PmeI- and PvuI-digested genomic DNA, we obtained similar results (data not shown): fragment size differences between H1 and H2 were only observed when hybridizing with LCRAcen and LCRBtel and were comparable to those obtained with NotI-digested genomic DNA. This suggested that the fragment size differences between H1 and H2 were not due to polymorphic NotI restriction sites.



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  		Figure 4. PFGE analysis of the MAPT genomic region. (A) NotI restriction map predicted from the sequence contig of the MAPT genomic region annotated with LCR A and LCR B. The black arrow represents MAPT. Black dots show the location of the hybridization probes. (B) NotI restriction map reconstructed to fit H1 restriction patterns. Asterisks represent partially digested restriction sites. (C) PFGE analysis of a H1/H1 and H2/H2 and a H1/H2 individual. Probes are shown below, fragment sizes to the left of the autoradiograms.

 
We compared the sizes of observed with predicted restriction fragments based on in silico restriction digestion of the DNA sequence of the MAPT genomic region. Fragments hybridizing with probe LCRAcen were 60 kb longer, whereas those obtained with LCRBtel were 80 kb shorter than predicted (Fig. 4). This might suggest that sequence contigs and/or large-insert clone assemblies in the MAPT genomic contig were incorrect or, more likely, that the size of the LCRs is variable among individuals.

Evolution of MAPT haplotypes
In chimpanzee and gorilla (Gorilla gorilla), we successfully PCR amplified nine intronic sequences representing 5.5 kb of MAPT sequence distributed across the entire gene and containing 112 sequence differences including 44 H2 SNPs in human. In chimpanzee, we observed 17 H1 alleles and 25 H2 alleles, whereas two contained another nucleotide at the corresponding position; in gorilla, we observed 17 H1 alleles and 26 H2 alleles, whereas one contained another nucleotide at the corresponding position. This demonstrated that human H1 and H2 haplotypes are derivatives from an intermediate ancestral haplotype and accumulated a sizable number of sequence variations since their divergence. We compared the 114 sequence differences present in the 5.5 kb sequence of H1, H2, chimpanzee and gorilla, and assigned to the primate phylogenetic tree (Fig. 5). Given that chimpanzee speciation occurred 5.5 million years ago (10Go), we estimated that based on the number of variants on each branch, H1 and H2 diverted 3 million (17 mutations in human H2 branch) to 3.6 (27 mutations in human H1 branch) million years ago.



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  		Figure 5. Phylogenetic tree of human MAPT H1 and H2 haplotypes, chimpanzee and gorilla. The number of sequence differences based on analysis of 5.5 kb MAPT intronic sequence fragments is shown in each branch. The time scale of gorilla and chimpanzee speciation was taken from Kumar et al. (10Go). MYA: million years ago.

 

   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 RESULTS
 DISCUSSION
MATERIALS AND METHODS
 REFERENCES
 
MAPT mutations are accounting for <50% of FTD patients (2Go) and are invariably associated with pathological tau deposition in brain. However, of the FTD patients, >50% do not show tau depositions but have ubiquitin-staining, tau-negative inclusions (FTDU) or lack distinctive brain pathology (DLDH) (1Go). At least nine tau-negative FTD families, including both FTDU and DLDH families, were linked to chromosome 17q21 (2Go,11Go).

We significantly reduced the linked region in an informative FTDU-17 family 1083 to 4.8 cM between D17S1787 and D17S958 (3Go). In this study, we assembled and annotated the genomic sequence of the FTDU-17 region and demonstrated that it contained five LCRs including two BRCA1-NBR LCRs (12Go) and three MAPT LCRs A, B and C, members of a novel family of four MAPT LCRs. LCR A is located centromeric of MAPT and is inverted relative to LCRs B and C, located telomeric of MAPT. MAPT LCR D is located in the same orientation as MAPT LCR A at 17q24, 19 Mb telomeric of MAPT. Using STR-based LD mapping in the MAPT genomic region, we demonstrated that LCR A and LCR B flank the extended MAPT H1/H2 haplotypes (6Go–8Go) that resulted from a historical inversion (5Go). This suggested that the H1/H2 inversion is the result of non-allelic homologous recombination (NAHR) between LCR A and LCR B and comprised a 570 kb unique sequence between these LCRs. In family 1083, FTDU-17 segregated with the MAPT H1 haplotype (3Go), whereas in two Belgian FTD families, DR2 and DR8, conclusively linked to the MAPT genomic region in the absence of MAPT mutations (11Go), the disease was segregating with the MAPT H2 haplotype. These observations make it unlikely that the H1/H2 inversion underlies the genetic etiology of FTDU-17.

Because paracentric inversions are associated with reduced recombination (13Go), chances of observing informative recombination events occurring within the MAPT H1/H2 inversion are low. Since H2 is rare, this is especially true in families in which the linked chromosome carries a H2, taken that recombinations can only be observed in H2/H2 meioses. To exclude a role for MAPT in FTDU-17, we sequenced 138.5 kb of genomic MAPT including conserved upstream and downstream regulatory sequences in three patients of family 1083 and two unaffected relatives not carrying the disease haplotype. Mutations in non-coding regions of MAPT might affect, e.g. transcription, splicing or translation. Reduced levels of all mapt isoforms have been reported in patients of chromosome 17q21 linked hereditary dysphasic disinhibition dementia family 2 (14Go); however, these observations are controversial and could not be replicated in patients of other chromosome 17q21 linked families in which mapt proteins and levels seemed normal (15Go). During MAPT genomic sequencing, we identified 574 sequence variants. Only one variant, i.e. g.38276T>A located in MAPT intron 0, apparently segregated on the disease haplotype but was present with a rare A-allele frequency of 20.4% in 189 control individuals demonstrating that it was a common SNP and unrelated to FTDU-17. Although stretches of interspersed repeat elements and flanking sequences were excluded from our sequencing efforts, we cannot entirely exclude that variants in these repeat elements might contribute to FTDU-17. Examples of mutations in Alu elements leading to constitutive splicing of the element into the transcript, thereby leading to disease have been described, e.g. in mucopolysaccharidosis (16Go). Also, we cannot exclude a mutation in unknown distant regulatory elements of MAPT. In addition, direct genomic sequencing is unable to detect larger genomic deletions or insertions. However, we reported earlier heterozygous polymorphisms in all PCR amplicons containing MAPT exons except exons 10 and 12 (3Go). We demonstrated by quantitative PCR analysis of exons 10 and 12 that two copies were present in the patients' genome (data not shown). Moreover, since we included an H1/H2 patient in the MAPT genomic sequencing effort, we observed all 424 H2 variants in the heterozygous state in this patient. Together, these data exclude a major deletion in coding and non-coding regions of MAPT. Also, for all H2 variants, the peak heights in the sequence readouts were not supporting a complete or partial multiplication of MAPT. However, since currently we have no frozen brain material available of patients in family 1083, we could not confirm these genomic observations by qualitative and/or quantitative studies of MAPT transcripts. Nevertheless, normal brain transcript levels of MAPT were observed in another FTDU-17 family, family Dutch III (15Go).

Absence of insoluble tau-pathology in FTDU-17 brains, could suggest that a mutation outside MAPT affecting another positional candidate gene at 17q21 might be the underlying genetic cause. In this respect, it is important to note that the 6.53 Mb large FTDU-17 region is located in a gene-dense chromosomal segment. Sequence annotation efforts predicted the presence of 145 genes with known function and an additional 104 novel genes with unknown function. In patients of family 1083, we have already excluded mutations in exons and exon/intron boundaries of 13 positional candidate genes including PSH2 (4Go), STH (3Go), ADAM11, ATP6V0A1, CRF, GFAP, HAP1, LOC284058, MAP3K14, NSF, WNT3 and WNT9B and a novel kinesin gene represented by ESTs BM470271 [GenBank] , CN291085 [GenBank] , CV355787 [GenBank] , CN284941 [GenBank] , CD657231 [GenBank] and BI870026 [GenBank] (data not shown). However, we identified many additional functionally relevant positional candidate genes and massive mutation detection efforts are required to analyze them all. Therefore, it might be more efficient to first attempt to further reduce the FTDU-17 region by identification of informative meiotic recombinants in additional extended FTDU-17 families or ancestral recombinants in FTD patients that are associated with the FTDU-17 region.

Since we identified five LCRs inside the FTDU-17 region, one other possibility that remains to be examined is that FTDU-17 might be a genomic disorder (17Go) resulting from NAHR between the different LCRs. LCRs have been previously established as mediators of genome evolution associated with genomic rearrangements within the past 35 million years (18Go). Using several approaches, we provided evidence that the MAPT LCRs are unstable. Synteny mapping of human, mouse and chimpanzee indicated that LCR A is the progenitor sequence, of which a segmental duplication led to LCRs B–D. Also, at least two inversions of the chromosomal segments located between the MAPT LCRs must have occurred during evolution, most likely before chimpanzee speciation. Moreover, sequence comparison of 5.5 kb of MAPT intronic sequence in human, chimpanzee and gorilla demonstrated that one of these inversions must have occurred 3–3.6 million years ago, and to date is present in the human population as the MAPT H1/H2 inversion polymorphism. Further, Stefansson et al. (5Go) reported one to three tandem repeated copies of the gene segment containing the first 13 exons of NSF present in different H1 haplotypes; NSF is located in subunit 8 of LCR B (Fig. 2). Of interest, suppression of recombination between two major haplotypes has also been reported in the BRCA1 region at 17q21 (19Go). It is possible, though not yet proven, that the BRCA1-NBR LCRs—also located in the FTDU-17 region—are mediators of NAHR events resulting in a BRCA1 H1/H2 inversion existing in the human population as a common polymorphism. Together, these observations support our notion that the FTDU-17 region is unstable and prone to genomic mutations. Genomic rearrangements due to NAHR between paralogous sequences of LCRs are a common mechanism resulting in human disease (20Go). Although genomic rearrangements involving BRCA1-NBR LCRs have been associated with a substantial fraction of patients with familial ovarian/breast cancer (21Go), no inherited human disorder has yet been associated with rearrangements involving the MAPT LCRs. We excluded an abnormal copy number of the MAPT gene in FTDU-17 and abnormal MAPT transcripts have been excluded in other studies (15Go); however, we cannot exclude that a genomic mutation, e.g. affecting MAPT expression due to a position effect (22Go) might cause FTDU-17. Also, we cannot exclude a genomic mutation affecting a gene or genes other than MAPT. In this respect, we identified six genes located within the MAPT LCRs and sequence comparison of ESTs suggested that five genes are transcriptionally active. This observation does not prove functionality of the transcripts, since it has been shown earlier that LCR-derived genes are usually not functional due to gene rearrangements (23Go). However, we cannot exclude that due to rearrangements inside or between LCRs, aberrant genes or an abnormal copy number thereof might have arisen, leading to disease. To investigate these issues, in depth studies of the genomic structure of chromosome 17q21 in FTDU-17 patients, e.g. by extensive FISH and PFGE studies are needed. Finally, instability in the MAPT genomic region might also lead to somatic mutations and can therefore be a genetic cause of sporadic dementias, further increasing the importance of MAPT in neurodegeneration.

In conclusion, we showed that the FTDU-17 region is a gene-rich and genetically complex genomic region. In addition, genomic sequencing analysis of MAPT did not support the involvement of simple MAPT mutations in FTDU-17. Further analyses including mutation analyses of other positional candidate genes and structural analyses of the FTDU-17 region are required but time-consuming. Therefore, reduction of the FTDU-17 region through the identification of closer informative recombinants might be the most appropriate approach to advance the molecular genetic dissection of FTD. Identifying the genetic defect leading to FTDU-17, a disease which prevalence has long been underestimated, might provide new insights in the pathomechanism leading to FTDU-17 and related tauopathies.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 RESULTS
 DISCUSSION
 MATERIALS AND METHODS
REFERENCES
 
MAPT genomic sequencing
MAPT genomic sequencing was performed in 23 Caucasians including three patients of FTDU-17 family 1083 (III-11, III-26 and III-30) and two unaffected individuals not carrying the disease haplotype (III-14 and III-34) (3Go) as previously described (R. Rademakers et al., unpublished data). In short, 138.5 kb of MAPT (nucleotides 41323746–41462318 in GenBank accession no. NC_000017.9) including 3.9 kb upstream of intron 0 and and 3.7 kb downstream exon 13/14 that were conserved in rodent. PCR primers were developed to cover the complete genomic sequence with the exclusion of long stretches of interspersed repeat elements using SNPbox (24Go). Standard PCR reactions were performed and amplification products were purified, sequenced in both directions using the BigDye Terminator Cycle Sequencing v3.1 (Applied Biosystems) and analyzed on an ABI3730 DNA analyzer (Applied Biosystems). Sequences were analyzed using novoSNP (25Go) and by visual inspection of the sequence reads. For SNP g.38276T>A (numbering relative to AC091628 [GenBank] .2), a pyrosequencing assay was developed and 189 unrelated Dutch control individuals were analyzed.

Sequence assembly and annotation of the FTDU-17 region
Finished and unfinished large-insert human genomic sequences available in GenBank were identified with BLASTn (http://www.ncbi.nlm.nih.gov/BLAST) (26Go) using MAPT exon sequences and assembled into contigs. Obtained contigs were extended by performing iterative steps of BLASTn homology searches with contig end sequences and assembling newly identified sequences into the existing contigs until one contiguous sequence containing the complete FTDU-17 region was obtained. Later, when the human genome sequencing effort was completed in the MAPT region, the assembly was confirmed in NCBI Build 35 of the human genome using the UCSC human genome browser May 2004 assembly (http://genome.ucsc.edu) (27Go). The contig sequence was analyzed for LCR regions using YASS similarity searches (28Go) with expectation value 10 and the results were visualized as dot plots using an in-house developed software tool. Maximal local similarity between LCRs was identified by pair wise YASS analysis of the LCR sequences. To identify other genomic regions containing MAPT LCR sequences, all large-insert sequences related to LCR A available in GenBank were identified using megaBLAST and assembled into contigs. The chromosomal location of the sequence contigs was determined based on the position of their clones in the UCSC human genome browser. Genes located in the FTDU-17 region were identified using the UCSC human genome browser based on the location of mRNAs and spliced human ESTs. Sequences of transcripts located inside the LCRs were used to search paralogous transcripts in the other LCRs using BLAT in the UCSC human genome browser.

Synteny mapping
Orthologs of human MAP3K14 and CDC27, located centromeric of LCR A and telomeric of LCR C, respectively, were localized in the mouse (Mus musculus, NCBI genome Build 33) and chimpanzee (Pan troglodytes, NCBI Genome Build 1v1) genomes using the UCSC genome browser to identify syntenic regions and the gene order and orientations were identified. The DNA sequence of the mouse syntenic region was retrieved, repeat sequences were masked in mouse and human using RepeatMasker (29Go), orthologous regions were identified using YASS with expectation value of 10 and visualized as dot plots using an in-house developed software tool.

LD analysis of the MAPT region
The MAPT genomic sequence was searched for non-interrupted dinucleotide repeats with a length of at least 10 units using TRFinder (30Go) and PCR primers flanking the repeats were developed using Primer 3 (31Go) (primer sequences available on request). DNA of individuals of 23 nuclear, Caucasian families of Belgian origin composed of two parents and two children were PCR amplified and fragments were analyzed using an ABI3730 DNA-analyzer (Applied Biosystems). Alleles were scored using GENOTYPER and segregation analysis was performed in the nuclear families. MAPT H2 SNP16 (g.8117G>A; numbering according to GenBank accession no. AC091628.2) was genotyped in all individuals using pyrosequencing. Occurrences of the STR alleles on parental chromosomes with the MAPT H1 and H2 haplotypes were counted and differences of allele distribution were analyzed using CLUMP (32Go).

PFGE analyses
As previously described, 8 µg genomic DNA embedded in low-melting agarose plugs was digested overnight with 40 U NotI, PmeI or PvuI and separated on a CHEF Mapper XA (Biorad) using electrophoresis conditions calculated by the embedded algorithm for optimal fragment separation between 50 and 1000 kb. Saccharomyces cerevisiae chromosomes and {lambda} DNA ladder were used as size standards. After electrophoresis, the DNA was depurinated in 0.25 mM HCl for 7 min, denatured, neutralized and transferred to Hybond N+ nylon membranes (Amersham) using Southern blotting. Hybridization probes were generated by PCR using primers flanking LCR A, LCR B and MAPT at both sides (Fig. 4). Probes were verified by sequencing and labeled with [{alpha}-32GoP]dCTP and [{alpha}-32GoP]dATP by random primer labeling. Hybridization was carried out overnight at 55°C in UltraHyb hybridization buffer (Ambion). Membranes were washed in 0.5% SDS buffer containing decreasing concentrations of SSC until background signal disappeared. Autoradiography was performed overnight to 4 days.

Evolution of MAPT haplotypes
Ten PCR primer pairs, designed on the basis of the human MAPT intronic sequences, were used to amplify genomic DNA of two chimpanzees and one gorilla. Sequences in primates were compared with human MAPT H1 and H2 sequences and variants were located on the primate phylogenetic tree (10Go). On the basis of the number of mutations in each branch, the time of separation of human MAPT H1 and H2 haplotypes was determined taking human and chimpanzee speciation 5.5 million years ago as a reference (10Go).


   ACKNOWLEDGEMENTS
 
The authors are grateful to J. Vermeersch, of the Center for Human Genetics, University of Leuven (KUL), Belgium, for providing chimpanzee and gorilla DNA for the evolutionary studies of MAPT and to the personnel of the VIB8 Genetic Service Facility (http://www.vibgeneticservicefacility.be) for the genetic analyses. The Special Research Fund of the University of Antwerp, the Fund for Scientific Research Flanders (FWO-F), the Interuniversity Attraction Poles (IUAP) program P5/19 of the Belgian Science Policy Office (BELSPO), the International Alzheimer Research Foundation (IARF) Belgium and the EU contract LSHM-CT-2003-503330 (APOPIS) supported the research described in this paper. R.R. and M.C. are postdoctoral fellows of the FWO-F.

Conflict of Interest statement. None declared.


   FOOTNOTES
 
{dagger} The authors wish it to be known that, in their opinion, the first two authors should be regarded as joint First Authors. Back


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 RESULTS
 DISCUSSION
 MATERIALS AND METHODS
 REFERENCES
 

  1. Rosso, S.M., Donker, K.L., Baks, T., Joosse, M., de Koning, I., Pijnenburg, Y., de Jong, D., Dooijes, D., Kamphorst, W., Ravid, R. et al. (2003) Frontotemporal dementia in The Netherlands: patient characteristics and prevalence estimates from a population-based study. Brain, 126, 2016–2022.[Abstract/Free Full Text]

  2. Rademakers, R., Cruts, M. and van Broeckhoven, C. (2004) The role of tau (MAPT) in frontotemporal dementia and related tauopathies. Hum. Mutat., 24, 277–295.[CrossRef][Web of Science][Medline]

  3. Rademakers, R., Cruts, M., Dermaut, B., Sleegers, K., Rosso, S.M., van den Broeck, M., Backhovens, H., van Swieten, J., van Duijn, C.M. and van Broeckhoven, C. (2002) Tau negative frontal lobe dementia at 17q21: significant finemapping of the candidate region to a 4.8 cM interval. Mol. Psychiatry, 7, 1064–1074.[CrossRef][Web of Science][Medline]

  4. Rademakers, R., van den Broeck, M., Sleegers, K., van Duijn, C., van Broeckhoven, C. and Cruts, M. (2004) Absence of pathogenic mutations in presenilin homologue 2 in a conclusively 17-linked tau-negative dementia family. Neurogenetics, 5, 79–80.[CrossRef][Web of Science][Medline]

  5. Stefansson, H., Helgason, A., Thorleifsson, G., Steinthorsdottir, V., Masson, G., Barnard, J., Baker, A., Jonasdottir, A., Ingason, A., Gudnadottir, V.G. et al. (2005) A common inversion under selection in Europeans. Nat. Genet., 37, 129–137.[CrossRef][Web of Science][Medline]

  6. Pastor, P., Ezquerra, M., Perez, J.C., Chakraverty, S., Norton, J., Racette, B.A., McKeel, D., Perlmutter, J.S., Tolosa, E. and Goate, A.M. (2004) Novel haplotypes in 17q21 are associated with progressive supranuclear palsy. Ann. Neurol., 56, 249–258.[CrossRef][Web of Science][Medline]

  7. Pittman, A.M., Myers, A.J., Duckworth, J., Bryden, L., Hanson, M., Abou-Sleiman, P., Wood, N.W., Hardy, J., Lees, A. and de Silva, R. (2004) The structure of the tau haplotype in controls and in progressive supranuclear palsy. Hum. Mol. Genet., 13, 1267–1274.[Abstract/Free Full Text]

  8. Oliveira, S.A., Scott, W.K., Zhang, F., Stajich, J.M., Fujiwara, K., Hauser, M., Scott, B.L., Pericak-Vance, M.A., Vance, J.M. and Martin, E.R. (2004) Linkage disequilibrium and haplotype tagging polymorphisms in the Tau H1 haplotype. Neurogenetics, 5, 147–155.[CrossRef][Web of Science][Medline]

  9. Baker, M., Litvan, I., Houlden, H., Adamson, J., Dickson, D., Perez-Tur, J., Hardy, J., Lynch, T., Bigio, E. and Hutton, M. (1999) Association of an extended haplotype in the tau gene with progressive supranuclear palsy. Hum. Mol. Genet., 8, 711–715.[Abstract/Free Full Text]

  10. Kumar, S. and Hedges, S.B. (1998) A molecular timescale for vertebrate evolution. Nature, 392, 917–920.[CrossRef][Medline]

  11. Rademakers, R., van der Zee, J., Kumar-Singh, S., Dermaut, B., Cruts, M., and van Broeckhoven, C. (2005) In Cummings, J.L. (ed.), Genotype–Proteotype–Phenotype: Relationships in Neurodegenerative diseases. Springer-Verlag, Berlin, Heidelberg, pp. 119–139.

  12. Jin, H., Selfe, J., Whitehouse, C., Morris, J.R., Solomon, E. and Roberts, R.G. (2004) Structural evolution of the BRCA1 genomic region in primates. Genomics, 84, 1071–1082.[CrossRef][Web of Science][Medline]

  13. Brown, G.M., Leversha, M., Hulten, M., Ferguson-Smith, M.A., Affara, N.A. and Furlong, R.A. (1998) Genetic analysis of meiotic recombination in humans by use of sperm typing: reduced recombination within a heterozygous paracentric inversion of chromosome 9q32–q34.3. Am. J. Hum. Genet., 62, 1484–1492.[CrossRef][Web of Science][Medline]

  14. Zhukareva, V., Vogelsberg-Ragaglia, V., van Deerlin, V.M., Bruce, J., Shuck, T., Grossman, M., Clark, C.M., Arnold, S.E., Masliah, E., Galasko, D. et al. (2001) Loss of brain tau defines novel sporadic and familial tauopathies with frontotemporal dementia. Ann. Neurol., 49, 165–175.[CrossRef][Web of Science][Medline]

  15. Rosso, S.M., Kamphorst, W., de Graaf, B., Willemsen, R., Ravid, R., Niermeijer, M.F., Spillantini, M.G., Heutink, P. and van Swieten, J.C. (2001) Familial frontotemporal dementia with ubiquitin-positive inclusions is linked to chromosome 17q21-22. Brain, 124, 1948–1957.[Abstract/Free Full Text]

  16. Vervoort, R., Gitzelmann, R., Lissens, W. and Liebaers, I. (1998) A mutation (IVS8+0.6 kbdelTC) creating a new donor splice site activates a cryptic exon in an Alu-element in intron 8 of the human beta-glucuronidase gene. Hum. Genet., 103, 686–693.[Web of Science][Medline]

  17. Lupski, J.R. (1998) Genomic disorders: structural features of the genome can lead to DNA rearrangements and human disease traits. Trends Genet., 14, 417–422.[CrossRef][Web of Science][Medline]

  18. Bailey, J.A., Baertsch, R., Kent, W.J., Haussler, D. and Eichler, E.E. (2004) Hotspots of mammalian chromosomal evolution. Genome Biol., 5, R23.[CrossRef][Medline]

  19. Liu, X. and Barker, D.F. (1999) Evidence for effective suppression of recombination in the chromosome 17q21 segment spanning RNU2-BRCA1. Am. J. Hum. Genet., 64, 1427–1439.[CrossRef][Web of Science][Medline]

  20. Stankiewicz, P. and Lupski, J.R. (2002) Genome architecture, rearrangements and genomic disorders. Trends Genet., 18, 74–82.[CrossRef][Web of Science][Medline]

  21. Montagna, M., Dalla, P.M., Menin, C., Agata, S., de Nicolo, A., Chieco-Bianchi, L., and D'Andrea, E. (2003) Genomic rearrangements account for more than one-third of the BRCA1 mutations in northern Italian breast/ovarian cancer families. Hum. Mol. Genet., 12, 1055–1061.[Abstract/Free Full Text]

  22. Kleinjan, D.A. and van Heyningen, V (2005) Long-range control of gene expression: emerging mechanisms and disruption in disease. Am. J. Hum. Genet., 76, 8–32.[CrossRef][Web of Science][Medline]

  23. Samonte, R.V. and Eichler, E.E. (2002) Segmental duplications and the evolution of the primate genome. Nat. Rev. Genet., 3, 65–72.[Web of Science][Medline]

  24. Weckx, S., de Rijk, P., van Broeckhoven, C. and Del Favero, J. (2004) SNPbox, a modular software package for large scale primer design. Bioinformatics, 21, 385–387.

  25. Weckx, S., Del Favero, J., Rademakers, R., Claes, L., Cruts, M., de Jonghe, P., van Broeckhoven, C. and de Rijk, P. (2005) novoSNP, a novel computational tool for sequence variation discovery. Genome Res., 15, 436–442.[Abstract/Free Full Text]

  26. Altschul, S.F., Gish, W., Miller, W., Myers, E.W. and Lipman, D.J. (1990) Basic local alignment search tool. J. Mol. Biol., 215, 403–410.[CrossRef][Web of Science][Medline]

  27. Kent, W.J., Sugnet, C.W., Furey, T.S., Roskin, K.M., Pringle, T.H., Zahler, A.M. and Haussler, D. (2002) The human genome browser at UCSC. Genome Res., 12, 996–1006.[Abstract/Free Full Text]

  28. Noe, L. and Kucherov, G. (2003) YASS: similarity search in DNA sequences. Rapport de recherche de l'INRIA-Lorraine RR-4852.

  29. Smit, A.F.A., Hubley, R. and Green, P. RepeatMasker Open-3.0. 2004. http://www.repeatmasker.org.

  30. Benson, G. (1999) Tandem repeats finder: a program to analyze DNA sequences. Nucleic Acids Res., 27, 573–580.[Abstract/Free Full Text]

  31. Rozen, S. and Skaletsky, H. (2000) Primer3 on the WWW for general users and for biologist programmers. Methods Mol. Biol., 132, 365–386.[Medline]

  32. Sham, P.C. and Curtis, D. (1995) Monte Carlo tests for associations between disease and alleles at highly polymorphic loci. Ann. Hum. Genet., 59, 97–105.[Web of Science][Medline]

  33. Lopez-Correa, C., Dorschner, M., Brems, H., Lazaro, C., Clementi, M., Upadhyaya, M., Dooijes, D., Moog, U., Kehrer-Sawatzki, H., Rutkowski, J.L. et al. (2001) Recombination hotspot in NF1 microdeletion patients. Hum. Mol. Genet., 10, 1387–1392.[Abstract/Free Full Text]


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