Cloning and characterization of the mouse alpha1C/A-adrenergic receptor gene and analysis of an alpha1C promoter in cardiac myocytes: role of an MCAT element that binds transcriptional enhancer factor-1 (TEF-1)

Mol Pharmacol. 2001 May;59(5):1225-34. doi: 10.1124/mol.59.5.1225.

Abstract

alpha1-Adrenergic receptor (AR) subtypes in the heart are expressed by myocytes but not by fibroblasts, a feature that distinguishes alpha1-ARs from beta-ARs. Here we studied myocyte-specific expression of alpha1-ARs, focusing on the subtype alpha1C (also called alpha1A), a subtype implicated in cardiac hypertrophic signaling in rat models. We first cloned the mouse alpha1C-AR gene, which consisted of two exons with an 18 kb intron, similar to the alpha1B-AR gene. The receptor coding sequence was >90% homologous to that of rat and human. alpha1C-AR transcription in mouse heart was initiated from a single Inr consensus sequence at -588 from the ATG; this and a putative polyadenylation sequence 8.5 kb 3' could account for the predominant 11 kb alpha1C mRNA in mouse heart. A 5'-nontranscribed fragment of 4.4 kb was active as a promoter in cardiac myocytes but not in fibroblasts. Promoter activity in myocytes required a single muscle CAT (MCAT) element, and this MCAT bound in vitro to recombinant and endogenous transcriptional enhancer factor-1. Thus, alpha1C-AR transcription in cardiac myocytes shares MCAT dependence with other cardiac-specific genes, including the alpha- and beta-myosin heavy chains, skeletal alpha-actin, and brain natriuretic peptide. However, the mouse alpha1C gene was not transcribed in the neonatal heart and was not activated by alpha1-AR and other hypertrophic agonists in rat myocytes, and thus differed from other MCAT-dependent genes and the rat alpha1C gene.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Chloramphenicol O-Acetyltransferase / metabolism
  • Cloning, Molecular
  • DNA-Binding Proteins / metabolism*
  • Gene Expression Regulation* / drug effects
  • Heart / growth & development
  • Heart / physiology
  • Mice
  • Molecular Sequence Data
  • Myocardium / metabolism*
  • Norepinephrine / pharmacology
  • Promoter Regions, Genetic / genetics
  • RNA, Messenger / metabolism
  • Receptors, Adrenergic, alpha-1 / genetics*
  • Receptors, Adrenergic, alpha-1 / metabolism
  • Response Elements / drug effects
  • Response Elements / genetics
  • Sequence Homology, Amino Acid
  • TEA Domain Transcription Factors
  • Transcription Factors / metabolism*
  • Transcription, Genetic / drug effects

Substances

  • DNA-Binding Proteins
  • RNA, Messenger
  • Receptors, Adrenergic, alpha-1
  • TEA Domain Transcription Factors
  • Tead1 protein, mouse
  • Transcription Factors
  • Chloramphenicol O-Acetyltransferase
  • Norepinephrine

Associated data

  • GENBANK/AF362076
  • GENBANK/AF362077
  • GENBANK/AF362078
  • GENBANK/M60654
  • GENBANK/M60655