Early onset and differential temporospatial expression of melanopsin isoforms in the developing chicken retina.

DANIELA M VERRA; CONTIN MARIA ANA; HICKS DAVID; GUIDO MARIO EDUARDO

ASSOC RESEARCH VISION OPHTHALMOLOGY INC

Lugar: Jul 7;52(8):5111-20. Print 2011 Jul.; Año: 2011 vol. 52 p. 5111 - 5111

URPOSE. Retinal ganglion cells (RGCs) expressing the photopigment melanopsin (Opn4) display intrinsic photosensitivity. In this study, the presence of nonvisual phototransduction cascade components in the developing chicken retina and primary RGCs cultures was investigated, focusing on the two Opn4 genes: the Xenopus (Opn4x) and the mammalian (Opn4m) orthologs. METHODS. Retinas were dissected at different embryonic (E) and postnatal (P) days, and primary RGC cultures were obtained at E8 and kept for 1 hour to 5 days. Samples were processed for RT-PCR and immunochemistry. RESULTS. Embryonic retinas expressed the master eye gene Pax6, the prospective RGC specification gene Brn3, and components of the nonvisual phototransduction cascade, such as Opn4m and the G protein q (Gq) mRNAs at very early stages (E4 ?E5). By contrast, expression of photoreceptor cell markers (CRX, red-opsin, rhodopsin, and -transducin) was observed from E7 to E12. Opn4m protein was visualized in