Deletion of a remote enhancer near ATOH7 disrupts retinal neurogenesis, causing NCRNA disease

Individuals with nonsyndromic congenital retinal nonattachment (NCRNA) are totally blind from birth. The disease afflicts ∼1% of Kurdish people living in a group of neighboring villages in

North Khorasan, Iran. We found that NCRNA is caused by a 6,523-bp deletion that spans a remote cis regulatory element 20 kb upstream from ATOH7 (Math5), a bHLH transcription factor gene that

is required for retinal ganglion cell (RGC) and optic nerve development. In humans, the absence of RGCs stimulates massive neovascular growth of fetal blood vessels in the vitreous and

early retinal detachment. The remote ATOH7 element appears to act as a secondary or 'shadow' transcriptional enhancer. It has minimal sequence similarity to the primary enhancer, which is

close to the ATOH7 promoter, but drives transgene expression with an identical spatiotemporal pattern in the mouse retina. The human transgene also functions appropriately in zebrafish,

reflecting deep evolutionary conservation. These dual enhancers may reinforce ATOH7 expression during early critical stages of eye development when retinal neurogenesis is initiated.

The authors are grateful to A. Swaroop for facilitating this collaborative project, A. Aledavood for logistical support and encouragement, H. Parmar, J. Trobe and E. Oliver for help

interpreting MRI studies, L. Prasov for assistance with mouse tissue cDNAs and retinal dissections, J. Johnson for pBGn-Cherry plasmid DNA, N. Brown for Math5-GFP transgenic mice, I. Masai

forath5:GFP transgenic fish, M. Pihalja and M. Chiang for flow cytometry advice, S. Philips and T. Masud for screening candidate genes, S. Dagenais and R. Lyons for SNP genotyping analysis,

S. Barolo, N. Brown, L. Prasov, C. Chou, M. Meisler and B. Link for helpful suggestions, and to T. Saunders, M. van Keuren and the University of Michigan transgenic animal, flow cytometry

and DNA sequencing cores for technical support. We are profoundly grateful to NCRNA family members for their involvement and dedication to this study over many years. The research was funded

by grants from the Glaucoma Foundation and the University of Michigan Center for Genetics in Health and Medicine to T.G., and from the US National Institutes of Health to T.G. (EY14259),

D.G. (EY18132) and J.A.B. (T32 EY13934).

Present address: Present address:Department of Biological Structure, University of Washington,Seattle,Washington, USA.,

Neuroscience Research Center and Department of Medical Genetics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Department of Biology, Grand Valley State University, Allendale, Michigan, USA

Departments of Human Genetics and Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA

Ophthalmology Ward, Emam Ali Hospital, Bojnourd, North Khorasan, Iran

Department of Biochemistry, Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan, USA

N.M.G. and M.M. collected clinical data. N.M.G., D.D.R., J.A.B. and T.G. performed genomic and functional experiments. D.G. developed and bred transgenic fish. N.M.G., D.D.R., J.A.B., D.G.

and T.G. analyzed data and wrote the manuscript.

Supplementary Figures 1–10, Supplementary Tables 1–3 and Supplementary Note (PDF 905 kb)

Anyone you share the following link with will be able to read this content: