title: Autoregulation of retinal homeobox (rax) gene promoter activity through a highly conserved genomic element.
abstract: The Retinal homeobox (rax) gene is expressed in vertebrate retinal progenitor and stem cells and is essential for retinal development. In frogs, rax is expressed in the ciliary marginal zone (CMZ), a region containing retinal progenitor and stem cells at the anterior of the eye. Little is known regarding regulation of rax transcription and regulation of transcription of rax targets. We found that three ultra-conserved genomic elements (UCEs) flanking the rax coding region regulate expression of a rax promoter-GFP transgene in Xenopus tadpoles. One of these elements, UCE1, regulates expression of the transgene in the dorsal CMZ. UCE1 contains a Rax binding site, PCE-1. We demonstrate that rax regulates expression of the transgene through the PCE-1 site found in UCE1. Therefore, rax transcription in the CMZ is controlled, in part, by autoregulatory mechanisms.
authors.affiliation: Center for Molecular and Human Genetics, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA.
authors.forename: Lisa E
authors.initials: LE
authors.lastname: Kelly
authors.affiliation: Graduate Program in Molecular, Cellular, and Developmental Biology, College of Biological Sciences, Columbus, Ohio, USA.
authors.forename: Reyna I
authors.initials: RI
authors.lastname: Martinez-De Luna
authors.affiliation: Center for Molecular and Human Genetics, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA.|Graduate Program in Molecular, Cellular, and Developmental Biology, College of Biological Sciences, Columbus, Ohio, USA.|Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, Ohio, USA.
authors.forename: Heithem M
authors.initials: HM
authors.lastname: El-Hodiri
mesh_terms: D000818:Animals; D001665:Binding Sites; D017124:Conserved Sequence / Q000235:genetics; D005136:Eye Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D007814:Larva / Q000235:genetics / Q000254:growth & development; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D012160:Retina / Q000254:growth & development* / Q000378:metabolism; D014981:Xenopus / Q000235:genetics* / Q000254:growth & development; D029867:Xenopus Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism
chemical_list: D005136:Eye Proteins; C524416:Rax protein, Xenopus; D029867:Xenopus Proteins
keywords: Xenopus; ciliary marginal zone; genomic element; retinal homeobox gene; retinal progenitor cells