Loss of zebrafish Ataxin-7, a SAGA subunit responsible for SCA7 retinopathy, causes ocular coloboma and malformation of photoreceptors

被引:13
作者
Carrillo-Rosas, Samantha [1 ,2 ,3 ,4 ]
Weber, Chantal [1 ,2 ,3 ,4 ]
Fievet, Lorraine [1 ,2 ,3 ,4 ]
Messaddeq, Nadia [1 ,2 ,3 ,4 ]
Karam, Alice [1 ,2 ,3 ,4 ]
Trottier, Yvon [1 ,2 ,3 ,4 ]
机构
[1] Inst Genet & Mol & Cellular Biol IGBMC, F-67000 Illkirch Graffenstaden, France
[2] CNRS, UMR7104, F-67000 Illkirch Graffenstaden, France
[3] INSERM, U1254, F-67000 Illkirch Graffenstaden, France
[4] Univ Strasbourg, F-67000 Illkirch Graffenstaden, France
关键词
DOMINANT CEREBELLAR-ATAXIA; CONE-ROD DYSTROPHY; RETINAL DEGENERATION; MACULAR DYSTROPHY; EYE DEVELOPMENT; GENOME; ANOPHTHALMIA; MICROPHTHALMIA; EXPRESSION; TARGET;
D O I
10.1093/hmg/ddy401
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Polyglutamine (polyQ) expansion in Ataxin-7 (ATXN7) results in spinocerebellar ataxia type 7 (SCA7) and causes visual impairment. SCA7 photoreceptors progressively lose their outer segments (OSs), a structure essential for their visual function. ATXN7 is a subunit of the transcriptional coactivator Spt-Ada-GcnS Acetyltransferase complex, implicated in the development of the visual system in flies. To determine the function of ATXN7 in the vertebrate eye, we have inactivated ATXN7 in zebrafish. While ATXN7 depletion in flies led to gross retinal degeneration, in zebrafish, it primarily results in ocular coloboma, a structural malformation responsible for pediatric visual impairment in humans. ATXN7 inactivation leads to elevated Hedgehog signaling in the forebrain, causing an alteration of proximo-distal patterning of the optic vesicle during early eye development and coloboma. At later developmental stages, malformations of photoreceptors due to incomplete formation of their OSs are observed and correlate with altered expression of crx, a key transcription factor involved in the formation of photoreceptor OS. Therefore, we propose that a primary toxic effect of polyQ expansion is the alteration of ATXN7 function in the daily renewal of OS in SCA7. Together, our data indicate that ATXN7 plays an essential role in vertebrate eye morphogenesis and photoreceptor differentiation, and its loss of function may contribute to the development of human coloboma.
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页码:912 / 927
页数:16
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