CRX controls retinal expression of the X-linked juvenile retinoschisis (RS1) gene

Nucleic Acids Res. 2008 Nov;36(20):6523-34. doi: 10.1093/nar/gkn737. Epub 2008 Oct 16.

Abstract

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.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acetylation
  • Animals
  • Base Sequence
  • Binding Sites
  • Cell Line
  • Dogs
  • Eye Proteins / biosynthesis
  • Eye Proteins / genetics*
  • Histones / metabolism
  • Homeodomain Proteins / metabolism*
  • Humans
  • Mice
  • Molecular Sequence Data
  • Photoreceptor Cells, Vertebrate / metabolism
  • Promoter Regions, Genetic*
  • Response Elements
  • Retina / metabolism*
  • Retinal Bipolar Cells / metabolism
  • Trans-Activators / metabolism*
  • Transcriptional Activation
  • Xenopus laevis
  • p300-CBP Transcription Factors / metabolism

Substances

  • Eye Proteins
  • Histones
  • Homeodomain Proteins
  • RS1 protein, human
  • Trans-Activators
  • cone rod homeobox protein
  • p300-CBP Transcription Factors
  • p300-CBP-associated factor