title: Expression of 17beta-hydroxysteroid dehydrogenease in testis of the ascidian Ciona intestinalis [corrected].
abstract: Ascidians have been employed as model organisms in investigating spermatogenesis. 17beta-hydroxysteroid dehydrogenase (HSD) is a steroidogenic enzyme essential for invertebrate spermatogenesis. A homologue of HSD was found in the EST database of Ciona intestinalis and cloned. Sequence analysis showed significant homology to zebra fish, sea urchin and human 17beta-HSD. The gene has an open reading frame (ORF) of 918 nucleotides coding for a polypeptide of 306 amino acids and a calculated mass of 35-kDa. Immunoblotting with an antibody raised against HSD recognized a 35-kDa protein purified from the C. intestinalis testis. The HSD protein was localized in steroidogenic cells in the Ciona testis. These results suggest that C. intestinalis 17beta-HSD is equivalent to the enzyme of vertebrate Leydig cells and that 17beta-HSD could be a phylogenetic marker for organisms producing steroids.
authors.affiliation: Asamushi Marine Biological Station, Graduate School of Life Science, Tohoku University, Sakamoto, Asamushi, Aomori 039-350, Japan. hoyabiology@hanmail.net
authors.forename: Kang Hee
authors.initials: KH
authors.lastname: Kho
authors.forename: Kazuo
authors.initials: K
authors.lastname: Inaba
mesh_terms: D015067:17-Hydroxysteroid Dehydrogenases / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular / Q000379:methods*; D020224:Expressed Sequence Tags; D008297:Male; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D012689:Sequence Homology, Nucleic Acid; D013737:Testis / Q000201:enzymology*; D014561:Urochordata / Q000201:enzymology*
chemical_list: D015067:17-Hydroxysteroid Dehydrogenases