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.
Plant and Animal Cell Biotechnology Research Group, Korea Research Institute of Bioscience and Biotechnology, Taejon, Korea.
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Kang
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Lee
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Chung
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Lee
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