Differential phosphorylation of the transcription factor Oct1 during the cell cycle.
Orderly progression through the somatic cell division cycle is accompanied by phase-specific transcription of a variety of different genes. During S phase, transcription of mammalian histone H2B genes requires a specific promoter element and its cognate transcription factor Oct1 (OTF1). A possible mechanism for regulating histone H2B transcription during the cell cycle is direct modulation of Oct1 activity by phase-specific posttranslational modifications. Analysis of Oct1 during progression through the cell cycle revealed a complex temporal program of phosphorylation. A p34cdc2-related protein kinase that is active during mitosis may be responsible for one mitotic phosphorylation of Oct1. However, the temporally controlled appearance of Oct1 phosphopeptides suggests the involvement of multiple kinases and phosphatases. These results support the idea that cell cycle-regulated transcription factors may be direct substrates for phase-specific regulatory enzymes.
Roberts
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Howard Hughes Medical Institute, Laboratory of Molecular Biology, Rockefeller University, New York, NY 10021.
Segil
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Heintz
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D016203:CDC2 Protein Kinase / Q000378:metabolism; D002453:Cell Cycle; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D006367:HeLa Cells / Q000166:cytology / Q000502:physiology; D006657:Histones / Q000235:genetics; D051863:Host Cell Factor C1; D006801:Humans; D008938:Mitosis; D050811:Octamer Transcription Factor-1; D010449:Peptide Mapping; D010748:Phosphopeptides / Q000302:isolation & purification; D010766:Phosphorylation; D016196:S Phase; D014157:Transcription Factors / Q000302:isolation & purification / Q000378:metabolism*
D004268:DNA-Binding Proteins; C497692:HCFC1 protein, human; D006657:Histones; D051863:Host Cell Factor C1; D050811:Octamer Transcription Factor-1; C494165:POU2F1 protein, human; D010748:Phosphopeptides; D014157:Transcription Factors; D016203:CDC2 Protein Kinase