The fully linked HTML version of this article has now been published.
Development ePress online publication date 5 Jan 2005
doi: 10.1242/dev.01591
Research article: Development and disease
Duplicated genes with split functions: independent roles of protocadherin15 orthologues in zebrafish hearing and vision
Christoph Seiler,
Karin C. Finger-Baier,
Oliver Rinner,
Yuri V. Makhankov,
Heinz Schwarz,
Stephan C.F. Neuhauss,
and
Teresa Nicolson*
* Author for correspondence (e-mail: nicolson{at}ohsu.edu)
In the sensory receptors of both the eye and the ear, specialized apical structures have evolved to detect environmental stimuli such as light and sound. Despite the morphological divergence of these specialized structures and differing transduction mechanisms, the receptors appear to rely in part on a shared group of genes for function. For example, mutations in Usher (USH) genes cause a syndrome of visual and acoustic-vestibular deficits in humans. Several of the affected genes have been identified, including the USH1F gene, which encodes protocadherin 15 (PCDH15). Pcdh15 mutant mice also have both auditory and vestibular defects, although visual defects are not evident. Here we show that zebrafish have two closely related pcdh15 genes that are required for receptor-cell function and morphology in the eye or ear. Mutations in pcdh15a cause deafness and vestibular dysfunction, presumably because hair bundles of inner-ear receptors are splayed. Vision, however, is not affected in pcdh15a mutants. By contrast, reduction of pcdh15b activity using antisense morpholino oligonucleotides causes a visual defect. Optokinetic and electroretinogram responses are reduced in pcdh15b morpholino-injected larvae. In electron micrographs, morphant photoreceptor outer segments are improperly arranged, positioned perpendicular to the retinal pigment epithelium and are clumped together. Our results suggest that both cadherins act within their respective transduction organelles: Pcdh15a is necessary for integrity of the stereociliary bundle, whereas Pcdh15b is required for alignment and interdigitation of photoreceptor outer segments with the pigment epithelium. We conclude that after a duplication of pcdh15, one gene retained an essential function in the ear and the other in the eye.
This article has been cited by other articles:

|
 |

|
 |
 
Z.-L. Wang, X.-P. Xu, B.-L. He, S.-P. Weng, J. Xiao, L. Wang, T. Lin, X. Liu, Q. Wang, X.-Q. Yu, et al.
Infectious Spleen and Kidney Necrosis Virus ORF48R Functions as a New Viral Vascular Endothelial Growth Factor
J. Virol.,
May 1, 2008;
82(9):
4371 - 4383.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
R. J. L. Haywood-Watson II, Z. M. Ahmed, S. Kjellstrom, R. A. Bush, Y. Takada, L. L. Hampton, J. F. Battey, P. A. Sieving, and T. B. Friedman
Ames waltzer deaf mice have reduced electroretinogram amplitudes and complex alternative splicing of pcdh15 transcripts.
Invest. Ophthalmol. Vis. Sci.,
July 1, 2006;
47(7):
3074 - 3084.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
Z. M. Ahmed, R. Goodyear, S. Riazuddin, A. Lagziel, P. K. Legan, M. Behra, S. M. Burgess, K. S. Lilley, E. R. Wilcox, S. Riazuddin, et al.
The tip-link antigen, a protein associated with the transduction complex of sensory hair cells, is protocadherin-15.
J. Neurosci.,
June 28, 2006;
26(26):
7022 - 7034.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
K. Schlichting, M. Wilsch-Brauninger, F. Demontis, and C. Dahmann
Cadherin Cad99C is required for normal microvilli morphology in Drosophila follicle cells
J. Cell Sci.,
March 15, 2006;
119(6):
1184 - 1195.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
C. D'Alterio, D. D.D. Tran, M. W.Y. A. Yeung, M. S.H. Hwang, M. A. Li, C. J. Arana, V. K. Mulligan, M. Kubesh, P. Sharma, M. Chase, et al.
Drosophila melanogaster Cad99C, the orthologue of human Usher cadherin PCDH15, regulates the length of microvilli
J. Cell Biol.,
November 7, 2005;
171(3):
549 - 558.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. El-Amraoui and C. Petit
Usher I syndrome: unravelling the mechanisms that underlie the cohesion of the growing hair bundle in inner ear sensory cells
J. Cell Sci.,
October 15, 2005;
118(20):
4593 - 4603.
[Abstract]
[Full Text]
[PDF]
|
 |
|
© The Company of Biologists Ltd 2005