Human Molecular Genetics, Vol 8, 2369-2376, Copyright © 1999 by Oxford University Press
PE Martin, S L Coleman, SO Casalotti, A Forge and WH Evans
Three point mutations of the connexin26 (GJB2) gene associated with
hereditary deafness were studied using in vitro expression systems.
Mutation M34T results in an amino acid substitution in the first
transmembrane domain of the connexin protein, W77R is located in the second
transmembrane domain and W44C is in the first extracellular loop. Wild-type
and mutated connexin vectors were constructed and transfected into
communication-deficient HeLa cells to obtain transient expression of the
connexin proteins. Intercellular coupling was subsequently assessed by
examining transfer of Lucifer yellow between cells. All three mutations
resulted in impaired intercellular coupling. The mechanistic reasons for
the functional inadequacies of the mutated proteins were investigated.
First, intracellular trafficking and targeting of the expressed connexins
were determined by immunohistochemistry. Mutation W77R was inefficiently
targeted to the plasma membrane and retained in intracellular stores
whereas the other two were targeted to the plasma membrane. Oligomerization
assays showed that connexins M34T and W77R failed to assemble efficiently
into hexameric gap junction hemichannels, but the W44C mutation did so. A
cell-free translation system showed that the mutated proteins were inserted
into microsomal membranes but the mutations have different effects on the
post-translational properties of the expressed proteins. The results point
to the conclusion that mutations in the transmembrane domains of connexin
proteins influence gap junction assembly.
ARTICLES
Properties of connexin26 gap junctional proteins derived from mutations associated with non-syndromal heriditary deafness
Department of Medical Biochemistry, University of Wales College of Medicine, Heath Park, Cardiff CF4 4XN, UK and
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  A Arora, P J Minogue, X Liu, P K Addison, I Russel-Eggitt, A R Webster, D M Hunt, L Ebihara, E C Beyer, V M Berthoud, et al. A novel connexin50 mutation associated with congenital nuclear pulverulent cataracts J. Med. Genet., March 1, 2008; 45(3): 155 - 160. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. W. Yum, J. Zhang, V. Valiunas, G. Kanaporis, P. R. Brink, T. W. White, and S. S. Scherer Human connexin26 and connexin30 form functional heteromeric and heterotypic channels Am J Physiol Cell Physiol, September 1, 2007; 293(3): C1032 - C1048. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H-H M Dahl, S E Tobin, Z Poulakis, F W Rickards, X Xu, L Gillam, J Williams, K Saunders, B Cone-Wesson, and M Wake The contribution of GJB2 mutations to slight or mild hearing loss in Australian elementary school children J. Med. Genet., November 1, 2006; 43(11): 850 - 855. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Hibino and Y. Kurachi Molecular and physiological bases of the k+ circulation in the Mammalian inner ear. Physiology, October 1, 2006; 21: 336 - 345. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Bicego, M. Beltramello, S. Melchionda, M. Carella, V. Piazza, L. Zelante, F. F. Bukauskas, E. Arslan, E. Cama, S. Pantano, et al. Pathogenetic role of the deafness-related M34T mutation of Cx26 Hum. Mol. Genet., September 1, 2006; 15(17): 2569 - 2587. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Zhang, W. Tang, S. Ahmad, J. A. Sipp, P. Chen, and X. Lin Gap junction-mediated intercellular biochemical coupling in cochlear supporting cells is required for normal cochlear functions PNAS, October 18, 2005; 102(42): 15201 - 15206. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K Cryns, E Orzan, A Murgia, P L M Huygen, F Moreno, I del Castillo, G Parker Chamberlin, H Azaiez, S Prasad, R A Cucci, et al. A genotype-phenotype correlation for GJB2 (connexin 26) deafness J. Med. Genet., March 1, 2004; 41(3): 147 - 154. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. K. Marziano, S. O. Casalotti, A. E. Portelli, D. L. Becker, and A. Forge Mutations in the gene for connexin 26 (GJB2) that cause hearing loss have a dominant negative effect on connexin 30 Hum. Mol. Genet., April 15, 2003; 12(8): 805 - 812. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Oshima, T. Doi, K. Mitsuoka, S. Maeda, and Y. Fujiyoshi Roles of Met-34, Cys-64, and Arg-75 in the Assembly of Human Connexin 26. IMPLICATION FOR KEY AMINO ACID RESIDUES FOR CHANNEL FORMATION AND FUNCTION J. Biol. Chem., January 10, 2003; 278(3): 1807 - 1816. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Bitner-Glindzicz Hereditary deafness and phenotyping in humans Br. Med. Bull., October 1, 2002; 63(1): 73 - 94. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Gottfried, M. Landau, F. Glaser, W.-L. Di, J. Ophir, B. Mevorah, N. Ben-Tal, D. P. Kelsell, and K. B. Avraham A mutation in GJB3 is associated with recessive erythrokeratodermia variabilis (EKV) and leads to defective trafficking of the connexin 31 protein Hum. Mol. Genet., May 16, 2002; 11(11): 1311 - 1316. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. E. M. Martin, G. Blundell, S. Ahmad, R. J. Errington, and W. H. Evans Multiple pathways in the trafficking and assembly of connexin 26, 32 and 43 into gap junction intercellular communication channels J. Cell Sci., January 11, 2001; 114(21): 3845 - 3855. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Rouan, T. W. White, N. Brown, A. M. Taylor, T. W. Lucke, D. L. Paul, C. S. Munro, J. Uitto, M. B. Hodgins, and G. Richard trans-dominant inhibition of connexin-43 by mutant connexin-26: implications for dominant connexin disorders affecting epidermal differentiation J. Cell Sci., January 6, 2001; 114(11): 2105 - 2113. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J Houseman, L. A Ellis, A. Pagnamenta, W.-L. Di, S. Rickard, A. H Osborn, H.-H. M Dahl, G. R Taylor, M. Bitner-Glindzicz, W. Reardon, et al. Genetic analysis of the connexin-26 M34T variant: identification of genotype M34T/M34T segregating with mild-moderate non-syndromic sensorineural hearing loss J. Med. Genet., January 1, 2001; 38(1): 20 - 25. [Abstract] [Full Text]
|
|