Molecular cloning, molecular evolution and gene expression of cDNAs encoding thyrotropin-releasing hormone receptor subtypes in a teleost, the sockeye salmon (Oncorhynchus nerka)

Yuichi Saito, Miyuki Mekuchi, Noriaki Kobayashi, Makoto Kimura, Yasuhiro Aoki, Tomohiro Masuda, Teruo Azuma, Motohiro Fukami, Masayuki Iigo, Tadashi Yanagisawa

Research output: Contribution to journalArticlepeer-review

Abstract

Molecular cloning of thyrotropin-releasing hormone receptors (TRHR) was performed in a teleost, the sockeye salmon (Oncorhynchus nerka). Four different TRHR cDNAs were cloned and named TRHR1, TRHR2a, TRHR2b and TRHR3 based on their similarity to known TRHR subtypes in vertebrates. Important residues for TRH binding were conserved in deduced amino acid sequences of the three TRHR subtypes except for the TRHR2b. Seven transmembrane domains were predicted for TRHR1, TRHR2a and TRHR3 proteins but only five for TRHR2b which appears to be truncated. In silico database analysis identified putative TRHR sequences including invertebrate TRHR and reptilian, avian and mammalian TRHR3. Phylogenetic analyses predicted the molecular evolution of TRHR in vertebrates: from the common ancestral TRHR (i.e. invertebrate TRHR), the TRHR2 subtype diverged first and then TRHR1 and TRHR3 diverged. Reverse transcription-polymerase chain reaction analyses revealed TRHR1 transcripts in the brain (hypothalamus), retina, pituitary gland and large intestine; TRHR2a in the brain (telencephalon and hypothalamus); and TRHR3 in the brain (olfactory bulbs) and retina.

Original languageEnglish (US)
Pages (from-to)80-88
Number of pages9
JournalGeneral and Comparative Endocrinology
Volume174
Issue number2
DOIs
StatePublished - Nov 1 2011

Keywords

  • Molecular evolution
  • Sockeye salmon Oncorhynchus nerka
  • Teleosts
  • Thyrotropin-releasing hormone
  • Thyrotropin-releasing hormone receptor

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Endocrinology

Fingerprint Dive into the research topics of 'Molecular cloning, molecular evolution and gene expression of cDNAs encoding thyrotropin-releasing hormone receptor subtypes in a teleost, the sockeye salmon (Oncorhynchus nerka)'. Together they form a unique fingerprint.

Cite this