Open AccessMammalianβ-polymerase promoter: phosphorylation of ATF/CRE-binding protein and regulation of DNA binding
Author(s) -
Ella W. Englander,
Steven G. Widen,
Samuel H. Wilson
Publication year - 1991
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/19.12.3369
Subject(s) - biology , microbiology and biotechnology , promoter , binding site , gene , gene expression , biochemistry
The gene for the mammalian DNA repair enzyme DNA polymerase beta (beta-pol) is constitutively expressed in most cells, but is regulated in a tissue-specific fashion and can be induced in response to some types of DNA damaging agents. The promoter for the human beta-pol gene has been characterized and found to be TATA-less, but it does have multiple GC boxes and one ATF/CRE-binding site located within 50 residues 5' of the major mRNA start site. The ATF/CRE-binding site has been found to be essential for activity of the cloned promoter. We report that a bovine testes DNA-binding protein with specificity for the beta-pol promoter ATF/CRE-binding site is phosphorylated in vivo and contains several phosphorylation sites. Sequence specific DNA-binding by the purified protein is reduced when the natural protein is dephosphorylated or when it is hyperphosphorylated by protein kinase A (cKA) in vitro. These results suggest the possibility that phosphorylation systems may change binding of this ATF/CRE-binding protein to the beta-pol promoter and in turn modulate the promoter. Possible correlation of the results with transient expression activity of the cloned beta-pol promoter fusion gene was obtained in 293 cells. Cotransfection with a cKA expression plasmid to elevate phosphorylation was found to strongly reduce promoter activity.