Project description:The retinal ganglion cell (RGC) competence factor ATOH7 is dynamically expressed during retinal histogenesis. ATOH7 transcription is controlled by a promoter-adjacent primary enhancer and a remote shadow enhancer (SE). Deletion of the ATOH7 human SE causes non‑syndromic congenital retinal non-attachment (NCRNA) disease, characterized by optic nerve aplasia and total blindness. We used genome editing to model NCRNA in mice. Deletion of the murine SE reduces Atoh7 mRNA >5-fold, but does not recapitulate optic nerve loss; however, SEdel/KO (knockout) trans heterozygotes have thin optic nerves. By analyzing Atoh7 mRNA and protein levels, RGC development and survival, and chromatin landscape effects, we show how the SE ensures robust Atoh7 transcriptional output. Combining SE deletion, KO and wild-type alleles in a genotypic series, we determined the amount of Atoh7 needed to produce a normal complement of adult RGCs, and the secondary consequences of graded reductions in Atoh7 dosage. Together these data reveal the workings of an evolutionary fail-safe, a duplicate enhancer mechanism hard-wired in the machinery of vertebrate retinal ganglion cell genesis.
Project description:The microarray analysis was designed to test the effects of HES5.3 siRNAs, Atoh7 siRNAs and nt siRNAs on gene expression in embryonic chick retina.
Project description:The microarray analysis was designed to test the effects of Hes5.3 siRNAs, Atoh7 siRNAs and non-targeting siRNAs on gene expression at the periphery of the expanding Hes5.3 domain in embryonic chick retina. For this microarray we collected retina samples 16 hours after electroporation to complete our previous analysis performed on samples collected 36 hours after RNA interference treatment (Chiodini et al., 2013).
