Two isoforms of orthodenticle-related proteins (HpOtx) bind to the enhancer element of sea urchin arylsulfatase gene.
The sea urchin (Hemicentrotus pulcherrimus) arylsulfatase (HpArs) gene, expressed specifically in aboral ectoderm, contains a 229-bp enhancer in its first intron that is required for the activation of HpArs gene expression. Deletion analysis shows that a tandem repeat of orthodenticle-related protein (Otx) binding sites are responsible for the activity of this enhancer. Gel mobility shift analysis reveals that three types of Otx-proteins, which show different mobilities in gel shift assays, form complexes with the enhancer. Band I appears before hatching and gradually decreases by the gastrula stage. Band III appears at the blastula stage and Band II appears at the mesenchyme blastula stage; the levels of Band II and III remain constant until the gastrula stage. Two distinct types of HpOtx cDNA clones have been isolated from cDNA libraries of unfertilized eggs and gastrulae. Nucleotide sequences of the homeobox and downstream regions are well conserved in the two types of HpOtx cDNAs, while the region upstream from the homeobox has different nucleotide sequences. By genomic Southern blot analysis, only a single copy of HpOtx gene is detectable in the Hp genome, making it likely that two HpOtx isoforms are generated from the same gene. Results from Northern blot analysis confirm the presence of two types of HpOtx transcripts. Transcriptional regulation of the HpArs gene may, in part, be carried out through switching of Otx isoforms.
Sakamoto
N
N
Graduate Department of Gene Science, Faculty of Science, Hiroshima University, Japan.
Akasaka
K
K
Mitsunaga-Nakatsubo
K
K
Takata
K
K
Nishitani
T
T
Shimada
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001192:Arylsulfatases / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D001755:Blastocyst / Q000378:metabolism; D003001:Cloning, Molecular; D016384:Consensus Sequence; D029721:Drosophila Proteins; D004475:Ectoderm / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D004790:Enzyme Induction; D005775:Gastrula / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000737:chemistry*; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid; D012091:Repetitive Sequences, Nucleic Acid; D012617:Sea Urchins / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D017385:Sequence Homology; D014158:Transcription, Genetic
D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D011993:Recombinant Fusion Proteins; C093053:oc protein, Drosophila; D001192:Arylsulfatases