Cloning and characterization of the 5'-flanking region of the canine growth hormone gene.
The growth hormone (GH) gene is expressed in a variety of tissues outside the pituitary, including the mammary gland. GH expression in the mammary gland is stimulated by progestins. The local synthesis of mammary GH may provide a highly proliferative environment within the mammary gland that may contribute to the development or progression of mammary tumours. To elucidate the mechanism regulating mammary GH expression, we cloned the 5'-flanking region of the canine GH gene using inverse polymerase chain reaction. Gel-shift experiments showed that several sequences in the 5'-flanking region of the GH gene bind mammary nuclear proteins and may be involved in basal and progesterone-induced mammary GH expression. Sequence analysis and comparison with the GH promoters of human, rat, and mouse genes revealed a number of shared binding sites for transcription factors such as Pit-1, which is involved in pituitary GH expression, and for factors involved in the differentiation of lymphoid cells. Moreover, a putative binding site for the progesterone receptor (PR) was identified in all promoters, indicating that the progestin-induced expression of GH in mammary tissue is most probably a direct effect of activated PRs on the GH gene promoter and that this may occur in various species.
Lantinga-van Leeuwen
Irma S
IS
Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 8, 3584 CM Utrecht, The Netherlands.
Timmermans-Sprang
Elpetra A P
EA
Mol
Jan A
JA
D024506:5' Flanking Region; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D004285:Dogs / Q000235:genetics*; D013006:Growth Hormone / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D014157:Transcription Factors / Q000378:metabolism
D014157:Transcription Factors; D013006:Growth Hormone