Identification of two nuclear factor-binding domains on the chicken cardiac actin promoter: implications for regulation of the gene.
The cis-acting regions that appear to be involved in negative regulation of the chicken alpha-cardiac actin promoter both in vivo and in vitro have been identified. A nuclear factor(s) binding to the proximal region mapped over the TATA element between nucleotides -50 and -25. In the distal region, binding spanned nucleotides -136 to -112, a region that included a second CArG box (CArG2) 5' to the more familiar CCAAT-box (CArG1) consensus sequence. Nuclear factors binding to these different domains were found in both muscle and nonmuscle preparations but were detectable at considerably lower levels in tissues expressing the alpha-cardiac actin gene. In contrast, concentrations of the beta-actin CCAAT-box binding activity were similar in all extracts tested. The role of these factor-binding domains on the activity of the cardiac actin promoter in vivo and in vitro and the prevalence of the binding factors in nonmuscle extracts are consistent with the idea that these binding domains and their associated factors are involved in the tissue-restricted expression of cardiac actin through both positive and negative regulatory mechanisms. In the absence of negative regulatory factors, these same binding domains act synergistically, via other factors, to activate the cardiac actin promoter during myogenesis.
Quitschke
W W
WW
Laboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland 20892.
DePonti-Zilli
L
L
Lin
Z Y
ZY
Paterson
B M
BM
D000199:Actins / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000032:analysis; D002642:Chick Embryo; D004252:DNA Mutational Analysis; D004262:DNA Restriction Enzymes; D004268:DNA-Binding Proteins / Q000032:analysis*; D003850:Deoxyribonuclease I; D005786:Gene Expression Regulation; D005822:Genetic Vectors; D008969:Molecular Sequence Data; D009206:Myocardium / Q000032:analysis*; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D014157:Transcription Factors / Q000032:analysis; D014158:Transcription, Genetic
D000199:Actins; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D004262:DNA Restriction Enzymes; D003850:Deoxyribonuclease I