Human Molecular Genetics Advance Access originally published online on September 9, 2005
Human Molecular Genetics 2005 14(20):3035-3046; doi:10.1093/hmg/ddi336
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Mutation of the calcium channel gene Cacna1f disrupts calcium signaling, synaptic transmission and cellular organization in mouse retina
,

1Department of Oncology, 2Department of Biochemistry and Molecular Biology, 3Department of Medical Genetics, 4Department of Cell Biology and Anatomy, 5Department of Surgery, 6Lion's Sight Centre, 7Population Genomics, 8Neurosciences Research Groups and 9Institute of Maternal and Child Health, Faculty of Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1, 10Department of Physiology and Biophysics and 11Department of Ophthalmology and 12Retina Research Laboratory, Dalhousie University, Halifax, NS, Canada
* To whom correspondence should be addressed at: Department of Medical Genetics, Faculty of Medicine, University of Calgary, 3330 Hospital Drive, N.W., Calgary, Alberta, Canada T2N 4N1. Tel: +1 4032208387; Fax: +1 4032108119; Email: ntbech{at}ucalgary.ca
Received August 8, 2005; Accepted September 6, 2005
Retinal neural transmission represents a key function of the eye. Identifying the molecular components of this vital process is helped by studies of selected human genetic eye disorders. For example, mutations in the calcium channel subunit gene CACNA1F cause incomplete X-linked congenital stationary night blindness (CSNB2 or iCSNB), a human retinal disorder with abnormal electrophysiological response and visual impairments consistent with a retinal neurotransmission defect. To understand the subcellular basis of this retinal disorder, we generated a mouse with a loss-of-function mutation by inserting a self-excising Cre-lox-neo cassette into exon 7 of the murine orthologue, Cacna1f. Electroretinography of the mutant mouse revealed a scotopic a-wave of marginally reduced amplitude compared with the wild-type mouse and absence of the post-receptoral b-wave and oscillatory potentials. Cone ERG responses together with visual evoked potentials and multi-unit activity in the superior colliculus were also absent. Calcium imaging in Fluo-4 loaded retinal slices depolarized with KCl showed 90% less peak signal in the photoreceptor synapses of the Cacna1f mutant than in wild-type mice. The absence of post-receptoral ERG responses and the diminished photoreceptor calcium signals are consistent with a loss of Ca2+ channel function in photoreceptors. Immunocytochemistry showed no detectable Cav1.4 protein in the outer plexiform layer of Cacna1f-mutant mice, profound loss of photoreceptor synapses, and abnormal dendritic sprouting of second-order neurons in the photoreceptor layer. Together, these findings in the Cacna1f-mutant mouse reveal that the Cav1.4 calcium channel is vital for the functional assembly and/or maintenance and synaptic functions of photoreceptor ribbon synapses. Moreover, the outcome of this study provides critical clues to the pathophysiology of the human retinal channelopathy of X-linked incomplete CSNB.
The authors wish it to be known that, in their opinion, the first two authors should be regarded as joint First Authors.
Present address: Department of Biosciences, Cardiff University, Biomedical Sciences Building, Museum Avenue, Cardiff, UK.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
F. Haeseleer Interaction and Colocalization of CaBP4 and Unc119 (MRG4) in Photoreceptors Invest. Ophthalmol. Vis. Sci., June 1, 2008; 49(6): 2366 - 2375. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Rao, R. Dallman, S. Henderson, and C.-K. Chen G 5 Is Required for Normal Light Responses and Morphology of Retinal ON-Bipolar Cells J. Neurosci., December 19, 2007; 27(51): 14199 - 14204. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Lee, A. Jimenez, G. Cui, and F. Haeseleer Phosphorylation of the Ca2+-Binding Protein CaBP4 by Protein Kinase C {zeta} in Photoreceptors J. Neurosci., November 14, 2007; 27(46): 12743 - 12754. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Tsujikawa, Y. Omori, J. Biyanwila, and J. Malicki Mechanism of positioning the cell nucleus in vertebrate photoreceptors PNAS, September 11, 2007; 104(37): 14819 - 14824. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Okawa and A. P. Sampath Optimization of Single-Photon Response Transmission at the Rod-to-Rod Bipolar Synapse Physiology, August 1, 2007; 22(4): 279 - 286. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Jalkanen, N. T. Bech-Hansen, R. Tobias, E.-M. Sankila, M. Mantyjarvi, H. Forsius, A. de la Chapelle, and T. Alitalo A Novel CACNA1F Gene Mutation Causes Aland Island Eye Disease Invest. Ophthalmol. Vis. Sci., June 1, 2007; 48(6): 2498 - 2502. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Eliasieh, L. C. Liets, and L. M. Chalupa Cellular Reorganization in the Human Retina during Normal Aging Invest. Ophthalmol. Vis. Sci., June 1, 2007; 48(6): 2824 - 2830. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Yang, B. Pawlyk, X.-H. Wen, M. Adamian, M. Soloviev, N. Michaud, Y. Zhao, M. A. Sandberg, C. L. Makino, and T. Li Mpp4 is required for proper localization of plasma membrane calcium ATPases and maintenance of calcium homeostasis at the rod photoreceptor synaptic terminals Hum. Mol. Genet., May 1, 2007; 16(9): 1017 - 1029. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. A. Raven, E. C. T. Oh, A. Swaroop, and B. E. Reese Afferent Control of Horizontal Cell Morphology Revealed by Genetic Respecification of Rods and Cones J. Neurosci., March 28, 2007; 27(13): 3540 - 3547. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. W. Tedford and G. W. Zamponi Direct G Protein Modulation of Cav2 Calcium Channels Pharmacol. Rev., December 1, 2006; 58(4): 837 - 862. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. C. Liets, K. Eliasieh, D. A. van der List, and L. M. Chalupa Dendrites of rod bipolar cells sprout in normal aging retina PNAS, August 8, 2006; 103(32): 12156 - 12160. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. A. Wycisk, B. Budde, S. Feil, S. Skosyrski, F. Buzzi, J. Neidhardt, E. Glaus, P. Nurnberg, K. Ruether, and W. Berger Structural and Functional Abnormalities of Retinal Ribbon Synapses due to Cacna2d4 Mutation. Invest. Ophthalmol. Vis. Sci., August 1, 2006; 47(8): 3523 - 3530. [Abstract] [Full Text] [PDF] |
||||
![]() |
R Jalkanen, M Mantyjarvi, R Tobias, J Isosomppi, E-M Sankila, T Alitalo, and N T Bech-Hansen X linked cone-rod dystrophy, CORDX3, is caused by a mutation in the CACNA1F gene J. Med. Genet., August 1, 2006; 43(8): 699 - 704. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Khosravani and G. W. Zamponi Voltage-gated calcium channels and idiopathic generalized epilepsies. Physiol Rev, July 1, 2006; 86(3): 941 - 966. [Abstract] [Full Text] [PDF] |
||||







