Proximal upstream flanking sequences direct calcium regulation of the rat prolactin gene.
Previous investigations have shown that Ca2+ strongly and specifically stimulates endogenous PRL gene expression by GH3 cells. In this study, addition of Ca2+ to Ca2+-deprived GH3 cells yielded a large (ca. 8-fold) stimulation of transient expression of a transfected PRL-chloramphenical acetyltransferase (CAT) construct containing ca. 1 kilo-base-pair of the PRL promoter region, but only a slight (less than or equal to 2-fold) nonspecific stimulation of CAT activity directed by any of three control promoters: dihydrofolate reductase, Rous sarcoma virus, or thymidine kinase. In GH3 cells never deprived of Ca2+, expression of a PRL-CAT construct was specifically stimulated and inhibited, respectively, by the dihydropyridine voltage-dependent Ca2+ channel modulators Bay K8644 and nimodipine; Ca2+ can thus regulate expression of an exogenous PRL promoter in cells incubated under physiological Ca2+ conditions. By employing a combined protocol, in which Ca2+-deprived cells are exposed to Ca2+ in the presence of Bay K8644, a very large (greater than 35-fold) but still promoter-specific induction of expression of a PRL-CAT construct was obtained. Analysis of 5'-deleted PRL-CAT constructs implied that the PRL gene Ca2+ response element is contained entirely within the first 174 base pairs of upstream flanking DNA sequence.
Jackson
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AE
Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York, New York 10029.
Bancroft
C
C
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D004247:DNA / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects*; D008969:Molecular Sequence Data; D010911:Pituitary Neoplasms / Q000378:metabolism; D011388:Prolactin / Q000235:genetics*; D011401:Promoter Regions, Genetic; D051381:Rats; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D011388:Prolactin; D004247:DNA; D002118:Calcium