title: Regulation of photoreceptor gene transcription via a highly conserved transcriptional regulatory element byvsxgene products.
abstract: The photoreceptor conserved element-1 (PCE-1) sequence is found in the transcriptional regulatory regions of many genes expressed in photoreceptors. Theretinal homeobox (Rx or Rax)gene product functions by binding to PCE-1 sites. However, other transcriptional regulators have also been reported to bind to PCE-1. One of these,vsx2, is expressed in retinal progenitor and bipolar cells. The purpose of this study is to identifyXenopus laevis vsxgene products and characterizevsxgene product expression and function with respect to the PCE-1 site.
  
  
  
  X. laevis vsxgene products were amplified with PCR. Expression patterns were determined with in situ hybridization using whole or sectionedX. laevisembryos and digoxigenin- or fluorescein-labeled antisense riboprobes. DNA binding characteristics of thevsxgene products were analyzed with electrophoretic mobility shift assays (EMSAs) using in vitro translated proteins and radiolabeled oligonucleotide probes. Gene transactivation assays were performed using luciferase-based reporters and in vitro transcribed effector gene products, injected intoX. laevisembryos.
  
  
  
  We identified onevsx1and twovsx2gene products. The twovsx2gene products are generated by alternate mRNA splicing. We verified that these gene products are expressed in the developing retina and that expression resolves into distinct cell types in the mature retina. Finally, we found thatvsxgene products can bind the PCE-1 site in vitro and that the twovsx2isoforms have different gene transactivation activities.
  
  
  
  vsxgene products are expressed in the developing and mature neural retina.vsxgene products can bind the PCE-1 site in vitro and influence the expression of a rhodopsin promoter-luciferase reporter gene. The two isoforms ofvsxhave different gene transactivation activities in this reporter gene system.
authors.affiliation: Center for Molecular and Human Genetics, The Research Institute at Nationwide Children's Hospital, Columbus, OH.
authors.forename: Yi
authors.initials: Y
authors.lastname: Pan
authors.affiliation: Graduate Program in Molecular, Cellular, and Developmental Biology, The Ohio State University, Columbus, OH; Center for Childhood Cancer, The Research Institute at Nationwide Children's Hospital, Columbus, OH; Center for RNA Biology, Wexner Medical Center, The Ohio State University, Columbus, OH.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Comiskey
authors.affiliation: Center for Molecular and Human Genetics, The Research Institute at Nationwide Children's Hospital, Columbus, OH.
authors.forename: Lisa E
authors.initials: LE
authors.lastname: Kelly
authors.affiliation: Graduate Program in Molecular, Cellular, and Developmental Biology, The Ohio State University, Columbus, OH; Center for Childhood Cancer, The Research Institute at Nationwide Children's Hospital, Columbus, OH; Center for RNA Biology, Wexner Medical Center, The Ohio State University, Columbus, OH; Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH.
authors.forename: Dawn S
authors.initials: DS
authors.lastname: Chandler
authors.affiliation: Center for Molecular and Human Genetics, The Research Institute at Nationwide Children's Hospital, Columbus, OH; Graduate Program in Molecular, Cellular, and Developmental Biology, The Ohio State University, Columbus, OH; Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH.
authors.forename: Heithem M
authors.initials: HM
authors.lastname: El-Hodiri
mesh_terms: D000818:Animals; D024202:Electrophoretic Mobility Shift Assay; D005136:Eye Proteins / Q000235:genetics*; D005784:Gene Amplification; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000235:genetics*; D017403:In Situ Hybridization; D010786:Photoreceptor Cells / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D050436:Regulatory Elements, Transcriptional / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D029867:Xenopus Proteins / Q000235:genetics*; D014982:Xenopus laevis
chemical_list: D005136:Eye Proteins; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D029867:Xenopus Proteins