title: Genetic regulation of beta 2-adrenergic receptors in 3T3-L1 fibroblasts.
abstract: The beta 2-adrenergic receptor from mouse 3T3-L1 cells is up-regulated through genetic mechanisms by glucocorticoids and butyrate. To study the genetic regulation of these receptors, we sequenced a 5 kb region of genomic DNA from 3T3-L1 cells, containing the beta-adrenergic receptor gene and approx. 1.5 kb of both 5' and 3' flanking sequences. The sequence contained one copy of an 8 bp consensus sequence which can confer phorbol ester-responsiveness to genes. Phorbol esters attenuated the up-regulation of beta 2-adrenergic receptors by glucocorticoids but not by butyrate. This effect was probably due to a phorbol ester-induced decrease in glucocorticoid receptor number. Using methylation-sensitive restriction enzymes, we examined the methylation of a CG-rich region occurring 5' to the gene and did not detect any changes in methylation of this region upon dexamethasone or butyrate treatment. A total of 16 putative glucocorticoid response elements were found which may mediate the glucocorticoid-induced increase in beta 2-adrenergic receptors. A comparison of the regulatory sequences of the two beta-adrenergic receptor subtypes from human and mouse confirms the observed physiological controls of receptor subtype expression and offers an explanation as to why the subtypes differ in genetic regulation.
authors.affiliation: Department of Pharmacology, University of Pennsylvania, Philadelphia 19104.
authors.forename: M T
authors.initials: MT
authors.lastname: Nakada
authors.forename: K M
authors.initials: KM
authors.lastname: Haskell
authors.forename: D J
authors.initials: DJ
authors.lastname: Ecker
authors.forename: J M
authors.initials: JM
authors.lastname: Stadel
authors.forename: S T
authors.initials: ST
authors.lastname: Crooke
mesh_terms: D000818:Animals; D001483:Base Sequence; D002087:Butyrates / Q000494:pharmacology; D020148:Butyric Acid; D002478:Cells, Cultured; D004247:DNA; D003907:Dexamethasone / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D008745:Methylation; D051379:Mice; D008969:Molecular Sequence Data; D015240:Phorbol 12,13-Dibutyrate; D011943:Receptors, Adrenergic, beta / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid
chemical_list: D002087:Butyrates; D011943:Receptors, Adrenergic, beta; D020148:Butyric Acid; D015240:Phorbol 12,13-Dibutyrate; D003907:Dexamethasone; D004247:DNA