Biomaterial Database

Beta 1- and beta 2-adrenergic receptor expression in differentiating 3T3-L1 cells. Independent regulation at the level of mRNA. 1990

S J Guest, and J R Hadcock, and D C Watkins, and C C Malbon

Department of Pharmacology, State University of New York, Stony Brook 11794-8651.

Regulation of two highly homologous GTP-binding regulatory protein- (G-protein) linked receptors, beta 1- and beta 2-adrenergic receptors, was probed at the level of mRNA in differentiating 3T3-L1 cells. Expression of the two receptor subtypes at the protein level was defined by competition of radioligand binding with CGP-20712A, a highly selective beta 1-adrenergic antagonist. 3T3-L1 fibroblasts express equivalent levels of beta 1- and beta 2-adrenergic receptors. Following treatment with dexamethasone and isobutylmethyl xanthine (IBMX), 3T3-L1 cells differentiate to adipocytes and express 4-fold more receptor, predominantly beta 2-subtype (beta 1-/beta 2- ratio, 5:95). Regulation of beta 1- and beta 2-receptor mRNA levels by differentiation, as well as by steroid alone and IBMX alone was probed by DNA excess solution hybridization. A beta 1-receptor antisense probe was constructed from double-stranded DNA assembled from synthetic oligonucleotides. In untreated 3T3-L1 fibroblasts the steady-state levels of beta 1- and beta 2-adrenergic receptor mRNA were equivalent (approximately 1.2 amol mRNA/micrograms total cellular RNA). beta 2-Adrenergic receptor mRNA levels increased 3-fold as 3T3-L1 fibroblasts were differentiated to adiopcytes (day 7). mRNA levels for beta 1-adrenergic receptor, in contrast, increased at day 2, but thereafter declined, falling to less than 0.05 amol mRNA/micrograms total cellular RNA by day 7 in adipocytes. A 7-day challenge with dexamethasone reduced by 50% beta 1-adrenergic receptor mRNA levels. Treatment with IBMX alone reduced mRNA levels for both receptor subtypes. Neither steroid nor IBMX alone promoted differentiation. The present work, for the first time, demonstrates (i) the mRNA levels on a molar basis for two highly homologous G-protein-linked receptors expressed in a single cell, (ii) independent regulation of their mRNA levels that correlates well with receptor expression, and (iii), that it is differentiation in 3T3-L1 cells per se and not treatment with glucocorticoid or IBMX alone that promotes the up-regulation of the beta 2-receptor transcripts and down-regulation of beta 1-receptor transcripts.

UI	MeSH Term	Description	Entries
D007093	Imidazoles	Compounds containing 1,3-diazole, a five membered aromatic ring containing two nitrogen atoms separated by one of the carbons. Chemically reduced ones include IMIDAZOLINES and IMIDAZOLIDINES. Distinguish from 1,2-diazole (PYRAZOLES).
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009693	Nucleic Acid Hybridization	Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)	Genomic Hybridization,Acid Hybridization, Nucleic,Acid Hybridizations, Nucleic,Genomic Hybridizations,Hybridization, Genomic,Hybridization, Nucleic Acid,Hybridizations, Genomic,Hybridizations, Nucleic Acid,Nucleic Acid Hybridizations
D011943	Receptors, Adrenergic, beta	One of two major pharmacologically defined classes of adrenergic receptors. The beta adrenergic receptors play an important role in regulating CARDIAC MUSCLE contraction, SMOOTH MUSCLE relaxation, and GLYCOGENOLYSIS.	Adrenergic beta-Receptor,Adrenergic beta-Receptors,Receptors, beta-Adrenergic,beta Adrenergic Receptor,beta-Adrenergic Receptor,beta-Adrenergic Receptors,Receptor, Adrenergic, beta,Adrenergic Receptor, beta,Adrenergic beta Receptor,Adrenergic beta Receptors,Receptor, beta Adrenergic,Receptor, beta-Adrenergic,Receptors, beta Adrenergic,beta Adrenergic Receptors,beta-Receptor, Adrenergic,beta-Receptors, Adrenergic
D002454	Cell Differentiation	Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.	Differentiation, Cell,Cell Differentiations,Differentiations, Cell
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D003907	Dexamethasone	An anti-inflammatory 9-fluoro-glucocorticoid.	Hexadecadrol,Decaject,Decaject-L.A.,Decameth,Decaspray,Dexasone,Dexpak,Hexadrol,Maxidex,Methylfluorprednisolone,Millicorten,Oradexon,Decaject L.A.
D005347	Fibroblasts	Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.	Fibroblast
D005786	Gene Expression Regulation	Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.	Gene Action Regulation,Regulation of Gene Expression,Expression Regulation, Gene,Regulation, Gene Action,Regulation, Gene Expression
D000273	Adipose Tissue	Specialized connective tissue composed of fat cells (ADIPOCYTES). It is the site of stored FATS, usually in the form of TRIGLYCERIDES. In mammals, there are two types of adipose tissue, the WHITE FAT and the BROWN FAT. Their relative distributions vary in different species with most adipose tissue being white.	Fatty Tissue,Body Fat,Fat Pad,Fat Pads,Pad, Fat,Pads, Fat,Tissue, Adipose,Tissue, Fatty