title: Expression of genes for two C-type lectins during budding of the ascidian Polyandrocarpa misakiensis.
abstract: Two closely related cDNA fragments, named pTC14-1 and pTC14-2, encoding C-type lectins were cloned from the budding ascidian Polyandrocarpa misakiensis by means of the polymerase chain reaction. The amino acid sequence deduced from pTC14-1 was identical to that of a 14-kDa calcium-dependent galactose-binding lectin, TC-14, that had been purified from this species. Between the two clones, nucleotide sequence similarity was 90%, whilst that of the deduced amino acid sequences was 82%. The cDNA inserts of these clones hybridized weakly with each other. Antisense RNA probes prepared from these clones gave intense hybridization signals on Northern blots of the W strain, but very weak signals on those of the other strains. Therefore, both clones were suggested to originate from the W strain, but from two separate genes, since the base substitution was scattered throughout the entire translated region. The amount of TC14-1 mRNA increased during bud development, and peaked at 36 h after separation of the bud from the parental body wall. At this stage, extracellular matrix containing TC-14 lectin developed in the mesenchymal space around the morphogenetic region of the bud. There was much less TC14-2, than TC14-1 mRNA at every stage of bud development. TC14-1 and TC14-2 mRNAs were detected on Northern blots of RNAs from adults and growing buds, suggesting that these genes can be used as the earliest markers of budding in this species.
authors.affiliation: Department of Biology, Faculty of Science, Kochi University, 780, Kochi, Japan.
authors.forename: Masumi
authors.initials: M
authors.lastname: Shimada
authors.affiliation: Department of Biology, Faculty of Science, Kochi University, 780, Kochi, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Fujiwara
authors.affiliation: Department of Biology, Faculty of Science, Kochi University, 780, Kochi, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kawamura
keywords: Ascidian; Budding; C-type lectin; Gene expression; Molecular cloning