Cell cycle regulation of H2b histone octamer DNA-binding activity in Chinese hamster lung fibroblasts.
The promoter regions of H2b histone genes contain a 14-base-pair element which includes the octamer ATTTGCAT. Mutational analysis has implicated the octamer element in the cell cycle-dependent expression of H2b histone genes. In this report, we address the question of whether the DNA-binding activity of the octamer transcription factor is itself cell cycle regulated. By using a gel mobility shift assay, we measured the relative amounts of octamer-binding activity during various phases of the cell cycle in serum-synchronized Chinese hamster fibroblasts. We found that the activity increased approximately fivefold between late G1 phase and early S phase and then decreased threefold between late S phase and G2 phase. These cell cycle-dependent changes in octamer DNA-binding activity may in part account for the selective transcription of H2b histone genes in late G1 and S phases.
Ito
M
M
Department of Biochemistry, University of Southern California School of Medicine, Los Angeles 90033.
Sharma
A
A
Lee
A S
AS
Maxson
R
R
D000818:Animals; D001483:Base Sequence; D002453:Cell Cycle; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005786:Gene Expression Regulation; D006657:Histones / Q000235:genetics*; D008168:Lung / Q000166:cytology / Q000378:metabolism; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D006657:Histones; D004247:DNA