Control of late off-center cone bipolar cell differentiation and visual signaling by the homeobox gene Vsx1

摘要: Retinal bipolar cells are interneurons that transmit visual signals from photoreceptors to ganglion cells. Although the pathways mediated by have been well characterized, genes regulate their development and function largely unknown. To determine role in cell of homeobox gene Vsx1, whose retinal expression is restricted a major subset differentiating mature cone (CB) cells, we targeted mice. Bipolar fate was not altered absence Vsx1 function, because pan-bipolar markers Chx10 Ret-B1 continued be expressed inner nuclear layer neurons labeled Vsx1-targeting reporter gene, τLacZ. The specification, number, gross morphology on-center off-center (OFF)-CB defined τLacZ locus were also normal Vsx1τLacZ/Vsx1τLacZ However, terminal differentiation OFF-CB retina mice incomplete, as demonstrated substantial reduction at least four (recoverin, NK3R, Neto1, CaB5) for these interneurons. These molecular abnormalities associated with defects documented electroretinography vitro recordings specific signaling. In particular, there general light-mediated activity OFF, but on-center, Thus, required late heritable OFF pathway-specific defect.