title: Molecular cloning of cytochrome P450 side-chain cleavage and changes in its mRNA expression during gonadal development of brown hagfish, Paramyxine atami.
abstract: Since hagfishes are considered the most primitive vertebrate known, extant or extinct, studies on their reproduction are indispensable for understanding phylogenetic aspects of vertebrate reproduction. However, little information is available on the endocrine regulation of the gonadal function in the hagfish. Based on EST analysis of the testis of the brown hagfish (Paramyxine atami), P450 side chain cleavage (CYP11A), which is the first and essential enzyme for steroidogenesis in jawed vertebrates, was cloned. The deduced amino acid sequence of hagfish CYP11A shows high identity to other animal forms especially in two functional domains, adrenodoxin binding domain and heme-binding domain. In the phylogenetic analysis, hagfish CYP11A forms a clade with the vertebrate CYP11A. Following the real-time PCR analysis, CYP11A mRNA expression levels were clearly correlated to the developmental stages of gonads in both sexes of the brown hagfish. By in situ hybridization, CYP11A mRNA signals were found in the theca cells of the ovarian follicles and Leydig cells and the tubule-boundary cells of the testis. These molecular and histological evidences are suggesting that CYP11A plays functional roles as a steroidogenic enzyme in gonadal development. Moreover, native GTH purified from hagfish pituitary stimulated the transcriptional levels of CYP11A in the organ-cultured testis in vitro, clearly suggesting that the steroidogenic activity of the hagfish is under the control of the pituitary GTH. It is suggested that vertebrates, during their early evolution, have established the pituitary-gonadal reproductive system.
authors.affiliation: Sado Marine Biological Station, Faculty of Science, Niigata University, Tassha, Sado, Niigata 952-2135, Japan; Graduate School of Science and Technology, Niigata University, Nishi-ku, Niigata, Niigata 950-2181, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Nishiyama
authors.affiliation: Department of Marine Biology and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, Kibanadai-nishi, Miyazaki 889-2192, Japan.
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Uchida
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, Ten-noudai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Abe
authors.affiliation: Sado Marine Biological Station, Faculty of Science, Niigata University, Tassha, Sado, Niigata 952-2135, Japan. Electronic address: nozaki@cc.niigata-u.ac.jp.
authors.forename: Masumi
authors.initials: M
authors.lastname: Nozaki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006066:Gonads / Q000166:cytology* / Q000378:metabolism*; D006196:Hagfishes / Q000502:physiology*; D017403:In Situ Hybridization; D007985:Leydig Cells / Q000166:cytology / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D006080:Ovarian Follicle / Q000166:cytology / Q000378:metabolism; D010802:Phylogeny; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012098:Reproduction / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D013737:Testis / Q000166:cytology / Q000378:metabolism; D013799:Theca Cells / Q000166:cytology / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D002786:Cholesterol Side-Chain Cleavage Enzyme
keywords: CYP11A; Gonadotropin; Hagfish; Leydig cell; Theca cell