 |
|||||
|
|||||
|
|||||
|
|||||
|
|||||
The Journal of Neuroscience, July 30, 2008, 28(31):7748-7764; doi:10.1523/JNEUROSCI.0397-08.2008
Previous Article | Next Article
Development/Plasticity/Repair
A Core Paired-Type and POU Homeodomain-Containing Transcription Factor Program Drives Retinal Bipolar Cell Gene Expression
Douglas S. Kim,1 Takahiko Matsuda,1 andConstance L. Cepko1,2 1Department of Genetics and 2Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115
Correspondence should be addressed to Constance L. Cepko, Howard Hughes Medical Institute, Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115. Email: cepko{at}genetics.med.harvard.edu
The diversity of cell types found within the vertebrate CNS arises in part from action of complex transcriptional programs. In the retina, the programs driving diversification of various cell types have not been completely elucidated. To investigate gene regulatory networks that underlie formation and function of one retinal circuit component, the bipolar cell, transcriptional regulation of three bipolar cell-enriched genes was analyzed. Using in vivo retinal DNA transfection and reporter gene constructs, a 200 bp Grm6 enhancer sequence, a 445 bp Cabp5 promoter sequence, and a 164 bp Chx10 enhancer sequence, were defined, each driving reporter expression specifically in distinct but overlapping bipolar cell subtypes. Bioinformatic analysis of sequences revealed the presence of potential paired-type and POU homeodomain-containing transcription factor binding sites, which were shown to be critical for reporter expression through deletion studies. The paired-type homeodomain transcription factors (TFs) Crx and Otx2 and the POU homeodomain factor Brn2 are expressed in bipolar cells and interacted with the predicted binding sequences as assessed by electrophoretic mobility shift assay. Grm6, Cabp5, and Chx10 reporter activity was reduced in Otx2 loss-of-function retinas. Endogenous gene expression of bipolar cell molecular markers was also dependent on paired-type homeodomain-containing TFs, as assessed by RNA in situ hybridization and reverse transcription-PCR in mutant retinas. Cabp5 and Chx10 reporter expression was reduced in dominant-negative Brn2-transfected retinas. The paired-type and POU homeodomain-containing TFs Otx2 and Brn2 together appear to play a common role in regulating gene expression in retinal bipolar cells.
Key words: retina; bipolar cells; transcription factor; metabotropic glutamate receptor 6; calcium-binding protein 5; Chx10
Received Jan. 29, 2008; revised May 28, 2008; accepted June 16, 2008.
Correspondence should be addressed to Constance L. Cepko, Howard Hughes Medical Institute, Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115. Email: cepko{at}genetics.med.harvard.edu
This article has been cited by other articles:
Y. Zhang, E. Ivanova, A. Bi, and Z.-H. Pan
Ectopic Expression of Multiple Microbial Rhodopsins Restores ON and OFF Light Responses in Retinas with Photoreceptor Degeneration
J. Neurosci., July 22, 2009; 29(29): 9186 - 9196.
[Abstract] [Full Text] [PDF]
H. Wassle, C. Puller, F. Muller, and S. Haverkamp
Cone Contacts, Mosaics, and Territories of Bipolar Cells in the Mouse Retina
J. Neurosci., January 7, 2009; 29(1): 106 - 117.
[Abstract] [Full Text] [PDF]
|
|
|
|
 |
|