Molecular cloning and localization of the luteinizing hormone β subunit and glycoprotein hormone α subunit from Japanese anchovy Engraulis japonicus

M. Ohkubo, S. Katayama, A. Shimizu

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Although Clupeiformes contain many economically important species, there is limited information on their reproductive physiology. To obtain more insight into reproductive mechanisms in clupeiform fishes, molecular cloning of the Japanese anchovy Engraulis japonicus luteinizing hormone β (LH. β) and glycoprotein hormone α (GPH. α) subunits, and immunocytochemistry of gonadotrophs in the pituitary using antisera raised against the synthetic peptides for both subunits were carried out. The cDNAs for LH. β and GPH. α subunits consisted of 963 and 535 nucleotides encoding 141 and 122 amino acids, respectively. The deduced amino acid sequences of the E. japonicus LH. β subunit showed a 60% similarity to the Pacific herring Clupea pallasii LH. β subunit and 24-31% similarities to FSH. β subunits of other fish species. The E. japonicus GPH. α subunit showed 52-57% similarities to anguilliform and cypriniform GPH. α subunits. Both the subunits have typical structural characteristics of each subunit such as N-linked glycosylation sites, conserved cysteine residues and highly conserved short amino acid sequences. These results indicate that cDNAs cloned in this study encode the E. japonicus LH. β and GPH. α subunits. Reverse-transcription polymerase chain reaction (RT-PCR) revealed that both the LH. β and GPH. α subunit genes were abundantly expressed in the pituitary, and the GPH. α subunit was observed to be weakly expressed in the extrapituitary tissues. Immunocytochemistry of the E. japonicus pituitary showed that cells that immunoreacted with antiserum against the LH. β subunit were distributed in the peripheral regions of proximal pars distalis, and these cells were also immunoreactive to antiserum against the GPH. α subunit. An abundant number of both LH. β and GPH. α cells in the pituitary of matured fish were observed, in comparison with immature fish. These results indicate that the E. japonicus LH is involved in the final reproductive maturation as well as those of other teleosts.

Original languageEnglish
Pages (from-to)372-387
Number of pages16
JournalJournal of Fish Biology
Volume77
Issue number2
DOIs
Publication statusPublished - 2010 Aug
Externally publishedYes

Keywords

  • Cloning
  • Clupeiformes
  • Gonadotroph
  • Gonadotropin
  • Immunocytochemistry
  • Japanese anchovy
  • Pituitary

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science

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