| Co-Investigator(Kenkyū-buntansha) |
YAMAKAWA Minoru National, Institute of Sericultural and Entomological Science, Department of Ins, 昆虫農業技術研究所・生体情報部, 室長 (30183677)
TANAKA Minoru Mie University School of Medicine, Department of Biochemistry, Instructor, 医学部, 講師 (90024736)
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| Research Abstract |
Four novel prolactin-like hormone cDNA clones have been isolated from a bovine term placenta cDNA library. We designated these clones as bovine prolactin-like protein (bPLP)-I, II. III and IV. bPLP-I, II, III, IV showed 50, 48, 43 and 48% homology of amino acid sequence with that of bovine prolactin, respectively. With bovine growth hormone, however, they showed only 23, 23, 22 and 22% homology, respectively. bPLP-I, on the other hand, was identical except for the N-terminal amino acid residue with bovine placental lactogen. bPLP-I has Val as N-terminal. when bovine placental lactogen has Ala for that position. Predicted mature forms of bPLP-I, II, III and IV are composed of 201, 202, 203 and 201 amino acid residues, respectively. Gene expressions of these four novel prolactin-like hormones the in bovine placenta have been analyzed by Northern blot hybridization and turned out to be stage-specific being maximal in the full-term-placenta. Thus, four novel bovine placental hormones bPLP-I, II, III and IV, resembled prolactin more closely than a growth hormone, and were distinct from placental lactogen. And these new hormones were considered to play important roles in metabolism and growth of the bovine fetus.
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