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XB-ART-12989
J Biol Chem May 28, 1999; 274 (22): 15590-7.

Immediate upstream sequence of arrestin directs rod-specific expression in Xenopus.

Mani SS , Besharse JC , Knox BE .


Abstract
Arrestins are a family of proteins that modulate G protein-coupled receptor responses with distinct arrestin genes expressed in rods and cones. To understand the regulatory mechanisms controlling rod-specific expression, the abundant Xenopus rod arrestin cDNA and a partial genomic clone, containing the immediate upstream region and amino terminus of the polypeptide, have been characterized. The deduced polypeptide has approximately 69% identity to other vertebrate rod arrestins. Southern blot analysis and polymerase chain reaction of intronic sequences demonstrated multiple alleles for rod arrestin. DNase I footprinting with retinal proteins revealed four major DNA binding sites in the proximal promoter, coinciding with consensus sequences reported in mammalian promoters. Purified bovine Crx homeodomain and mouse Nrl proteins protected a number of these sites. A dual approach of transient embryo transfections and transgenesis was used to locate transcriptional control sequences essential for rod-specific expression in Xenopus. Constructs containing -1287/+113 of 5'' upstream sequence with or without intron 1 directed high level expression, specifically in rods. A construct containing only -287/+113 directed expression of green fluorescent protein solely in rod cells. These results suggest that the Crx and Nrl binding sites in the proximal promoter are the primary cis-acting sequences regulating arrestin gene expression in rods.

PubMed ID: 10336455
Article link: J Biol Chem
Grant support: [+]

Species referenced: Xenopus
Genes referenced: arrb1 arrb2 crx cyp26a1 nrl rpe sag


Article Images: [+] show captions