A comparison of human O6-methylguanine-DNA methyltransferase promoter activity in Mer+ and Mer- cells.
The activity of the human O6-methylguanine-DNA methyltransferase (MGMT) gene promoter was determined in eight human cell lines by measuring chloramphenicol acetyltransferase activity in a reporter gene system. MGMT promoter activities in cells that do not express MGMT (Mer-) fell within the range of activities seen in cells that do express MGMT (Mer+). The promoter region contains 11 potential binding sites for the transcription factor Sp1, but no correlation was seen between cellular Sp1 protein and MGMT promoter chloramphenicol acetyltransferase activity. Because Mer- cells are not deficient in the factors needed for transcription of MGMT, we suggest that at least two mechanisms regulate MGMT expression. One suppresses MGMT mRNA and protein in Mer- cells, and another regulates the levels of constitutive expression in Mer+ cells. Sp1 is not a limiting factor in MGMT expression.
Harris
L C
LC
Department of Biochemical and Clinical Pharmacology, St. Jude Children's Research Hospital, Memphis, Tennessee 38101-0318.
Potter
P M
PM
Remack
J S
JS
Brent
T P
TP
D015153:Blotting, Western; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D008780:Methyltransferases / Q000235:genetics*; D019853:O(6)-Methylguanine-DNA Methyltransferase; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology*; D016329:Sp1 Transcription Factor / Q000502:physiology; D014162:Transfection; D014407:Tumor Cells, Cultured
D016329:Sp1 Transcription Factor; D008780:Methyltransferases; D019853:O(6)-Methylguanine-DNA Methyltransferase; D015500:Chloramphenicol O-Acetyltransferase