title: Regulation of spblimp1/krox1a, an alternatively transcribed isoform expressed in midgut and hindgut of the sea urchin gastrula.
abstract: The sea urchin regulatory gene Spblimp1/krox produces alternatively transcribed and spliced isoforms, 1a and 1b, which have different temporal and spatial patterns of expression. Here we describe a cis-regulatory module that controls the expression of the 1a splice form in the midgut and hindgut at the beginning of gastrulation. Conserved sequence patches revealed by a comparison of the blimp1/krox locus in Strongylocentrotus purpuratus and Lytechinus variegatus genomes were tested by gene transfer, in association with GFP or CAT reporter genes. An expression construct containing a conserved sequence patch immediately 5' of exon 1a included the transcription initiation site for blimp1/krox1a. This construct displays specific mid and hindgut expression, indicating that these are the locations of endogenous blimp1/krox1a transcription during the gastrula stage. Its sequence contains binding sites for Brn1/2/4, Otx, and Blimp1/Krox itself, as predicted in a prior regulatory network analysis.
authors.affiliation: Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Carolina B
authors.initials: CB
authors.lastname: Livi
authors.forename: Eric H
authors.initials: EH
authors.lastname: Davidson
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D019521:Body Patterning; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D004247:DNA / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D004064:Digestive System / Q000254:growth & development / Q000378:metabolism; D005775:Gastrula / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D047331:Lytechinus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008969:Molecular Sequence Data; D012617:Sea Urchins / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D013045:Species Specificity; D047270:Strongylocentrotus purpuratus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; C106226:Krox1 protein, Strongylocentrotus purpuratus; D014157:Transcription Factors; D004247:DNA