Nucleic Acids Research Advance Access originally published online on October 16, 2008
Nucleic Acids Research 2008 36(20):6523-6534; doi:10.1093/nar/gkn737
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Nucleic Acids Research, 2008, Vol. 36, No. 20 6523-6534
© 2008 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Gene regulation, Chromatin and Epigenetics |
CRX controls retinal expression of the X-linked juvenile retinoschisis (RS1) gene
1Institute of Human Genetics, University of Regensburg, Regensburg, Germany and 2Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada
*To whom correspondence should be addressed. Tel: +49 941 944 5400; Fax: +49 941 944 5402; Email: bweb{at}klinik.uni-regensburg.de
Received July 2, 2008. Revised October 1, 2008. Accepted October 2, 2008.
X-linked juvenile retinoschisis is a heritable condition of the retina in males caused by mutations in the RS1 gene. Still, the cellular function and retina-specific expression of RS1 are poorly understood. To address the latter issue, we characterized the minimal promoter driving expression of RS1 in the retina. Binding site prediction, site-directed mutagenesis, and reporter assays suggest an essential role of two nearby cone-rod homeobox (CRX)-responsive elements (CRE) in the proximal –177/+32 RS1 promoter. Chromatin immunoprecipitation associates the RS1 promoter in vivo with CRX, the coactivators CBP, P300, GCN5 and acetylated histone H3. Transgenic Xenopus laevis expressing a green fluorescent protein (GFP) reporter under the control of RS1 promoter sequences show that the –177/+32 fragment drives GFP expression in photoreceptors and bipolar cells. Mutating either of the two conserved CRX binding sites results in strongly decreased RS1 expression. Despite the presence of sequence motifs in the promoter, NRL and NR2E3 appear not to be essential for RS1 expression. Together, our in vitro and in vivo results indicate that two CRE sites in the minimal RS1 promoter region control retinal RS1 expression and establish CRX as a key factor driving this expression.
The authors wish it to be known that, in their opinion, the first two authors should be regarded as joint First Authors