| First Author | Park KU | Year | 2017 |
| Journal | Invest Ophthalmol Vis Sci | Volume | 58 |
| Issue | 2 | Pages | 1137-1150 |
| PubMed ID | 28199486 | Mgi Jnum | J:240687 |
| Mgi Id | MGI:5888939 | Doi | 10.1167/iovs.16-19767 |
| Citation | Park KU, et al. (2017) Gsg1, Trnp1, and Tmem215 Mark Subpopulations of Bipolar Interneurons in the Mouse Retina. Invest Ophthalmol Vis Sci 58(2):1137-1150 |
| abstractText | Purpose: How retinal bipolar cell interneurons are specified and assigned to specialized subtypes is only partially understood. In part, this is due to a lack of early pan- and subtype-specific bipolar cell markers. To discover these factors, we identified genes that were upregulated in Blimp1 (Prdm1) mutant retinas, which exhibit precocious bipolar cell development. Methods: Postnatal day (P)2 retinas from Blimp1 conditional knock-out (CKO) mice and controls were processed for RNA sequencing. Genes that increased at least 45% and were statistically different between conditions were considered candidate bipolar-specific factors. Candidates were further evaluated by RT-PCR, in situ hybridization, and immunohistochemistry. Knock-in Tmem215-LacZ mice were used to better trace retinal expression. Results: A comparison between Blimp1 CKO and control RNA-seq datasets revealed approximately 40 significantly upregulated genes. We characterized the expression of three genes that have no known function in the retina, Gsg1 (germ cell associated gene), Trnp1 (TMF-regulated nuclear protein), and Tmem215 (a predicted transmembrane protein). Germ cell associated gene appeared restricted to a small subset of cone bipolars while Trnp1 was seen in all ON type bipolar cells. Using Tmem215-LacZ heterozygous knock-in mice, we observed that beta-galactosidase expression started early in bipolar cell development. In adults, Tmem215 was expressed by a subset of ON and OFF cone bipolar cells. Conclusions: We have identified Gsg1, Tmem215, and Trnp1 as novel bipolar subtype-specific genes. The spatial and temporal pattern of their expression is consistent with a role in controlling bipolar subtype fate choice, differentiation, or physiology. |
