Prolactin-inducible enhancer activity of the first intron of the bovine beta-casein gene.
We have analyzed the regulatory roles of the first intron (intron-1) of the bovine beta-casein gene in the bovine beta-casein/CAT expression system using a mouse mammary epithelial cell line, HC11. After a combined treatment of HC11 cells with insulin, dexamethasone and prolactin, the induced expression of p beta c1.8/+ICAT vector including 2 kb intron-1 and 1.8 kb promoter was greatly increased to 23.5 folds, while that of p beta ca.8CAT basic vector with 1.8 kb promoter only, was 6.5. A classical enhancer activity was shown in the 2 kb intron fragment from the experiment in which the orientation and the position of the intron-1 on the vectors were changed. The enhancer activity was largely dependent on the lactogenic hormones, especially prolactin. A stepwise reduction of the inducibility in the 5' to 3' deletion analysis of the intron-1 indicates the existence of several functional elements in the region. In particular, an internal fragment (+1071 to +1490) was important for the prolactin-dependent enhancing activity of the intron-1. These results suggest that several elements in the intron-1 of the bovine beta-casein gene cooperatively interact not only with each other but also with its promoter for hormonal induction.
Kang
Y K
YK
Plant and Animal Cell Biotechnology Research Group, Korea Research Institute of Bioscience and Biotechnology, Taejon, Korea.
Lee
C S
CS
Chung
A S
AS
Lee
K K
KK
D000818:Animals; D002364:Caseins / Q000187:drug effects / Q000235:genetics*; D002417:Cattle; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D003907:Dexamethasone / Q000494:pharmacology; D004742:Enhancer Elements, Genetic / Q000187:drug effects* / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D005796:Genes / Q000187:drug effects* / Q000235:genetics; D005822:Genetic Vectors / Q000235:genetics; D005938:Glucocorticoids / Q000494:pharmacology; D006728:Hormones / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007438:Introns / Q000187:drug effects* / Q000235:genetics; D008969:Molecular Sequence Data; D011388:Prolactin / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D017384:Sequence Deletion / Q000235:genetics
D002364:Caseins; D005938:Glucocorticoids; D006728:Hormones; D007004:Hypoglycemic Agents; D007328:Insulin; D011994:Recombinant Proteins; D003907:Dexamethasone; D011388:Prolactin; D015500:Chloramphenicol O-Acetyltransferase