1996年9月
Hydropathy profiles of predicted thyrotropin-releasing hormone precursors are highly conserved despite low similarity of primary structures
JOURNAL OF NEUROENDOCRINOLOGY
- ,
- ,
- ,
- 巻
- 8
- 号
- 9
- 開始ページ
- 695
- 終了ページ
- 701
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1046/j.1365-2826.1996.05065.x
- 出版者・発行元
- BLACKWELL SCIENCE LTD
Two types of cDNAs encoding thyrotropin-releasing hormone (TRH) precursors (TRH-A andTRH-B) were amplified from hypothalamic mRNA of sockeye salmon by reverse transcriptase-polymerase chain reaction (RT-PCR). The amplification was achieved using two primers which correspond to TRH progenitor sequence (Lys/Arg-Arg-Gln-His-Pro-Gly-Lys/Arg-Arg). A full length cDNA encoding TRH-A was obtained by 5'- and 5'-RACE methods. It has a length of 1324 base pairs (bp) that contains sequences of 5' and 3' untranslated regions and an open reading frame of 259 codons. The sockeye salmon TRH-A deduced from the nucleotide sequence tandemly contains 8 copies of TRH progenitor sequences. Another cDNA which encodes a part of TRH-B consists of 242 bp, and the sequence homology between TRH-A and -B cDNAs is 90%. The result of Southern blot analysis of sockeye and masu salmon genomic DNAs supported the evidence that there are at least two TRH genes in the salmonid. A RT-PCR analysis of TRH gene expression in various tissues of sockeye salmon showed that strong expression was observed only in the brain. The primary structure of the sockeye salmon TRH-A shares low similarity to those of human, rat and Xenopus TRH precursors (35, 27 and 44%, respectively). However, their hydropathy profiles were almost the same with each other, The profile of sockeye salmon TRH-A showed the presence of two discrete hydrophobic regions, one in the N-terminal region which corresponds to the signal peptide and the other in the C-terminal region, All of the repetitive TRH progenitor sequences are included in three hydrophilic regions easily recognizable, The present results thus suggest that the three-dimensional structures of TRH precursors are highly conserved, although the primary structures of TRH precursors have diverged through the evolutionary pathway of vertebrates.
- リンク情報
- ID情報
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- DOI : 10.1046/j.1365-2826.1996.05065.x
- ISSN : 0953-8194
- PubMed ID : 8877818
- Web of Science ID : WOS:A1996VF64400005