title: Novel 3beta-hydroxysteroid dehydrogenases from gonads of the Nile tilapia: phylogenetic significance and expression during reproductive cycle.
abstract: Multiple forms of 3beta-hydroxysteroid dehydrogenase/isomerase (3beta-HSD) and their differential tissue expression pattern have not been shown in any lower vertebrates. In the present study, we report cloning of two novel 3beta-HSDs and two variants from gonads of the Nile tilapia. 3beta-HSD cDNAs encode two peptides of 375 (3beta-HSD type-I/variant 1) and 367 (3beta-HSD type-II/variant 1) amino acid residues that share 31.9% homology. 3beta-HSD type-I/variant 1 shared high homology with other piscine counterparts while 3beta-HSD type-II/variant 1 exhibited homology to mammalian DeltaC27-3beta-HSD and multifunctional viral 3beta-HSD. The latter seems to be ancient form among vertebrates. Transiently transfected 3beta-HSDs' open reading frames in COS-7 cells converted exogenous pregnenolone/androsta-5-ene-3beta-17beta-diol to progesterone/testosterone. Tissue distribution pattern of 3beta-HSDs by RT-PCR revealed varied expression pattern. Northern blot analysis of 3beta-HSDs demonstrated steady or gradual rise in transcripts level at different gonadal stages. These data revealed the importance of novel 3beta-HSDs in teleosts and also provided phylogenetic significance.
authors.affiliation: Laboratory of Reproductive Biology, National Institute for Basic Biology, Myodaiji, Okazaki 444-8585, Japan. bsksl@uohyd.ernet.in
authors.forename: B
authors.initials: B
authors.lastname: Senthilkumaran
authors.forename: C C
authors.initials: CC
authors.lastname: Sudhakumari
authors.forename: D S
authors.initials: DS
authors.lastname: Wang
authors.forename: G
authors.initials: G
authors.lastname: Sreenivasulu
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
authors.forename: H-K
authors.initials: HK
authors.lastname: Kobayashi
authors.forename: M
authors.initials: M
authors.lastname: Yoshikuni
authors.forename: Y
authors.initials: Y
authors.lastname: Nagahama
mesh_terms: D015067:17-Hydroxysteroid Dehydrogenases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D019556:COS Cells; D002522:Chlorocebus aethiops; D023681:Cichlids / Q000378:metabolism*; D003001:Cloning, Molecular; D005260:Female; D020869:Gene Expression Profiling; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010053:Ovary / Q000201:enzymology*; D010802:Phylogeny; D012098:Reproduction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013737:Testis / Q000201:enzymology*; D014162:Transfection
chemical_list: D007527:Isoenzymes; D015067:17-Hydroxysteroid Dehydrogenases; C044256:3 (or 17)-beta-hydroxysteroid dehydrogenase