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Ovarian 3,β‐hydroxysteroid dehydrogenase/Δ 5‐4 ‐isomerase of rainbow trout: Its cDNA cloning and properties of the enzyme expressed in a mammalian cell
Author(s) -
Sakai Noriyoshi,
Tanaka Minoru,
Takahashi Mika,
Fukada Sachiko,
Ian Mason J.,
Nagahama Yoshitaka
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)00795-0
Subject(s) - complementary dna , trout , rainbow trout , biology , microbiology and biotechnology , hydroxysteroid , cdna library , gene , biochemistry , enzyme , dehydrogenase , fishery , fish <actinopterygii>
A cDNA clone encoding 3β‐hydroxysteroid dehydrogenase/Δ 5‐4 ‐isomerase (3β‐HSD) was isolated from a cDNA library of rainbow trout ovarian thecal cells. Southern hybridization analysis of trout genomic DNA with the cDNA suggested the presence of a single gene encoding 3β‐HSD in the rainbow trout showing a total genomic size of less than 4 kilobases (kb). The cDNA hybridized to a single species of mRNA isolated from rainbow trout ovaries; the 1.4 kb transcripts were most abundant in trout ovaries during the later stages of oogenesis. The trout 3β‐HSD expressed in non‐steroidogenic monkey kidney tumor (COS‐1) cells showed a unique enzymatic 3β‐HSD activity. Dehydroepiandrosterone was a more favoral substrate of the trout 3β‐HSD than 17α‐hydroxypregnenolone. Interestingly, the trout 3β‐HSD expressed in COS‐1 cells exhibited minimal ability to convert pregnenolone to progesterone.