Visual system homeobox 1 (Vsx1) is a paired-like:CVC homeodomain
transcription factor that is expressed in a subset of retinal bipolar cells. Vsx1-null mice
have previously been shown to have defects in bipolar cell terminal differentiation
characterized by the reduced expression of four OFF bipolar cell-specific markers and
electrophysiological defects in the OFF visual signaling pathway. The availability of
recently identified bipolar cell markers enables a further characterization of the Vsx1-null
mutant. I determined that Vsx1 is expressed in Type 7 ON bipolar cells and observed the
upregulation of three cell markers: Cabp5, Chx10, and alpha-gustducin:GFP in this cell
type in Vsx1-null mice. These data reveal a trend in which Vsx1 functions as a
transcriptional repressor in Type 7 ON bipolar cells and as an activator in Type 2 OFF
bipolar cells. Lastly, my data indicate that Vsx1 is required for the expression of two
Type 3a bipolar cell markers, however, the mechanism by which it does so appears to be
complex, as I was unable to detect Vsx1 protein or reporter gene expression in this cell
type. / Graduate
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/3652 |
| Date | 03 November 2011 |
| Creators | Shi, Zhiwei |
| Contributors | Chow, Robert Lewis |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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