title: Complementary DNA cloning and expression of Pit-1/GHF-1 from the domestic turkey.
abstract: The transition from egg laying to incubation activity in birds is associated with a dramatic rise in serum prolactin levels. To further our understanding of the regulation of prolactin gene expression in birds, a cDNA clone encoding turkey Pit-1/GHF-1 was isolated. The turkey cDNA, designated tPit-1/GHF-1, was 1,123 nucleotides in length and encoded a protein of 327 amino acids, including a conserved 80-amino-acid POU-specific domain and a 60-amino-acid POU homeodomain. tPit-1/GHF-1 POU-specific domain and POU-homeodomain showed 94-95% amino acid identity with the corresponding rat Pit-1/GHF-1 domains. At its amino terminus, tPit-1/GHF-1 contained a 26-amino-acid insertion comparable to that found in the rat variant isoform, Pit-1 beta. Two other insertions of 38 and 7 amino acids were present and were not found in the mammalian protein. Levels of tPit-1/GHF-1 mRNA in pituitary tissue were examined at different phases of the turkey reproductive cycle by Northern blotting. tPit-1/GHF-1 mRNA was expressed as a 3.5-kb transcript, whose abundance remained relatively constant throughout the reproductive cycle. Thus, the dramatic rise in prolactin mRNA, observed during hyperprolactinemia in incubating turkey hens, was not associated with a concomitant increase in tPit-1/GHF-1 gene expression.
authors.affiliation: Department of Animal Science, Virginia Polytechnic Institute and State University, Blacksburg 24061-0306.
authors.forename: E A
authors.initials: EA
authors.lastname: Wong
authors.forename: J L
authors.initials: JL
authors.lastname: Silsby
authors.forename: M E
authors.initials: ME
authors.lastname: el Halawani
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA; D015342:DNA Probes; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D010902:Pituitary Gland / Q000378:metabolism; D011388:Prolactin / Q000097:blood / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D012098:Reproduction / Q000235:genetics; D012260:Ribonucleases / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D050817:Transcription Factor Pit-1; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D014422:Turkeys
chemical_list: D015342:DNA Probes; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D050817:Transcription Factor Pit-1; D014157:Transcription Factors; D011388:Prolactin; D004247:DNA; D012260:Ribonucleases