title: cis-acting negative regulatory element of prolactin gene.
abstract: The prolactin (PRL) gene in clonal strains of rat pituitary tumor cells in culture (GH cells) exhibit several regulatory responses, similar to the ones observed in rat pituitary gland. A comparative analysis of regulation of PRL gene expression in PRL-producing (PRL+) and PRL-nonproducing (PRL-) GH cells was conducted by monitoring the PRL promoter driven transient expression of chloramphenicol acetyltransferase (CAT) gene in GH4C1 (PRL+) and GH12C1 (PRL-) cells. The PRL promoter activity was drastically inhibited only in PRL-nonproducing cells (PRL-) and not in PRL producing cells (PRL+) when a 80-base pair (bp) DNA sequence from 5'-flanking region of PRL gene (located between -330 and -250 bp) was included in the PRL-CAT fusion gene constructs. Furthermore, a DNA/protein interaction involving this 80-bp DNA sequence and a 60-kDa nuclear protein was detected only in PRL- cells but not in PRL+ GH cells. These results suggested that the strain-specific suppression of PRL gene in PRL-, GH12C1 cells was mediated via interaction of a cis-acting negative regulatory element with a negative regulatory trans-acting factor in these cells. The negative regulatory element within the AT-rich 80-bp DNA sequence was mapped immediately adjacent to the site of interaction of trans-activators of PRL gene.
authors.affiliation: Laboratory of Molecular Biology, Harvard School of Dental Medicine, Boston, Massachusetts.
authors.forename: Z X
authors.initials: ZX
authors.lastname: Zhang
authors.forename: V
authors.initials: V
authors.lastname: Kumar
authors.forename: R T
authors.initials: RT
authors.lastname: Rivera
authors.forename: J
authors.initials: J
authors.lastname: Chisholm
authors.forename: D K
authors.initials: DK
authors.lastname: Biswas
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002999:Clone Cells; D004273:DNA, Neoplasm / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D005796:Genes; D013006:Growth Hormone / Q000235:genetics; D008969:Molecular Sequence Data; D010911:Pituitary Neoplasms; D011388:Prolactin / Q000235:genetics*; D011401:Promoter Regions, Genetic; D051381:Rats
chemical_list: D004273:DNA, Neoplasm; D011388:Prolactin; D013006:Growth Hormone