title: Toward understanding the morphogenesis of siliceous spicules in freshwater sponge: differential mRNA expression of spicule-type-specific silicatein genes in Ephydatia fluviatilis.
abstract: Siliceous spicules of sponges are morphologically diverse and provide good models for understanding the morphogenesis of biomineralized products. The silica deposition enzyme silicatein is a component of siliceous spicules of sponges and is thought to be the key molecule determining the morphology of spicules. Here, we focused on the silicateins of the freshwater sponge Ephydatia fluviatilis, which has two types of morphologically and functionally different spicules, called megascleres and gemmoscleres. We isolated six isoforms of silicateins and examined their mRNA expression in the cells producing megascleres and gemmoscleres. The spicule-type-specific mRNA expression of these isoforms and differential expression during spicule development suggest that the characteristic morphology of spicules is due to the specific properties and combinatory functions of silicatein isoforms.
authors.affiliation: Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku Kyoto, Japan.
authors.forename: Kurato
authors.initials: K
authors.lastname: Mohri
authors.forename: Mikiko
authors.initials: M
authors.lastname: Nakatsukasa
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Masuda
authors.forename: Kiyokazu
authors.initials: K
authors.lastname: Agata
authors.forename: Noriko
authors.initials: N
authors.lastname: Funayama
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002403:Cathepsins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D005618:Fresh Water; D018507:Gene Expression Regulation, Developmental; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009024:Morphogenesis; D010802:Phylogeny; D011161:Porifera / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development*; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D018076:DNA, Complementary; D007527:Isoenzymes; D012333:RNA, Messenger; D002403:Cathepsins