Mitosis-specific histone H3 phosphorylation in vitro in nucleosome structures.
A mechanism of mitosis-specific enhancement of histone H3 phosphorylation was analyzed in vitro in terms of nucleosome structure. The incorporation of [32P]phosphate into DNA-bound H3 was approximately 5-7 times higher than in DNA-free H3 using the catalytic subunit of cAMP-dependent protein kinase. The two major N-terminal serine sites, including the mitosis-specific site (Ser10) and Ser28, were extensively phosphorylated in the DNA-bound forms. These phosphorylation patterns were identical to those of nucleosomal H3. In contrast, the H3 in DNA-free octamers was very slightly phosphorylated. The major site of H3 phosphorylation in DNA-free H3 was Thr118 in the C-terminus. Results indicate that DNA-binding is essential for the high level of mitosis-specific H3 phosphorylation, and that the nucleosome structure promotes H3 N-terminal phosphorylation in vitro. It also suggests the possibility that H1 prevents H3 phosphorylation during interphase of the cell cycle.
Laboratory of Pharmaceutical Science, Nagoya City University, Japan.
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K
Shibata
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M
Inagaki
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K
Ajiro
D000818:Animals; D004247:DNA / Q000378:metabolism / Q000502:physiology; D006657:Histones / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology*; D009707:Nucleosomes / Q000378:metabolism* / Q000502:physiology; D010710:Phosphates / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D006657:Histones; D009707:Nucleosomes; D010710:Phosphates; D010761:Phosphorus Radioisotopes; D004247:DNA; D011494:Protein Kinases