title: cDNA sequence analysis, gene expression and protein localisation of the inhibin alpha-subunit of Australian brushtail possum (Trichosurus vulpecula).
abstract: An inhibin alpha-subunit cDNA sequence from the Australian brushtail possum (Trichosurus vulpecula) has been identified and analysed. The cDNA includes an open reading frame encoding a predicted precursor protein of 361 amino acids. The predicted protein sequence includes four possible proteolytic cleavage sites, 12 evolutionarily conserved cysteine residues and three potential N-linked glycosylation sites. The mature alpha-subunit is the carboxyl terminal fragment (alphaC) consisting of 131 amino acids. The full-length precursor protein shows a mean identity with eutherian homologues of 69.8%. The homology is not evenly distributed, with the putative alphaC fragment showing the highest level (79.7%). Using Northern hybridisation, an alpha-subunit transcript of approximately 1.6 kb was detected in adult possum ovary. Using in situ hybridisation and immunocytochemistry, inhibin alpha-subunit was localised exclusively to the granulosa cell layers of follicles. Hybridisation and immunostaining for the inhibin alpha-subunit were first observed in granulosa cells of primary follicles and the expression continued throughout all stages of follicular growth. Inhibin alpha-subunit mRNA and protein were also detected in cells of the corpus luteum. In summary, results indicate considerable conservation of the structure and possible function of the inhibin alpha-subunit protein since the divergence of the marsupial and eutherian mammalian lineages. The expression data suggest that, in the adult possum, inhibin may have a role in ovarian follicular growth from the primary stage of development.
authors.affiliation: AgResearch Wallaceville, Upper Hutt, New Zealand.
authors.forename: D
authors.initials: D
authors.lastname: Vanmontfort
authors.forename: A E
authors.initials: AE
authors.lastname: Fidler
authors.forename: D A
authors.initials: DA
authors.lastname: Heath
authors.forename: S B
authors.initials: SB
authors.lastname: Lawrence
authors.forename: D J
authors.initials: DJ
authors.lastname: Tisdall
authors.forename: P J
authors.initials: PJ
authors.lastname: Greenwood
authors.forename: K P
authors.initials: KP
authors.lastname: McNatty
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005260:Female; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007265:Inhibins; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D009893:Opossums; D010053:Ovary / Q000378:metabolism; D010455:Peptides / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D010455:Peptides; D012333:RNA, Messenger; C094377:inhibin-alpha subunit; D007265:Inhibins