title: Cell cycle changes in Physarum polycephalum histone H1 phosphate: relationship to deoxyribonucleic acid binding and chromosome condensation.
abstract: We have examined the relationship of phosphate content in histone H1 of Physarum polycephalum to mitotic chromosome condensation and affinity for deoxyribonucleic acid (DNA). H1 undergoes a series of posttranslational phosphorylations which increase its apparent molecular weight on NaDodSO4-polyacrylamide gels. Our studies confirm the observation by Bradbury and co-workers [Bradbury, E. M., Inglis, R. J., Matthews, H. R., & Sarner, N (1973) Eur. J. Biochem. 33, 131-139; Bradbury, E. M., Inglis, R. J., & Matthews, H. R. (1974) Nature (London) 247, 257-261] that the accumulation of phosphate in H1 increases markedly shortly before the onset of mitosis. However, we show in pulse-chase experiments with both 32PO4H1 and [14C]lysine H1 that there is no significant dephosphorylation of the histone either during or shortly after mitosis, suggesting that nonspecific postmitotic dephosphorylation of H1 is not a prerequisite for chromosome decondensation. We also show that both phosphorylated and unphosphorylated forms of H1 bind with somewhat greater affinity to single-stranded DNA-cellulose than to native DNA-cellulose and that phosphorylation weakens the affinity of H1 to both forms of DNA-cellulose.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002453:Cell Cycle; D002875:Chromosomes / Q000502:physiology*; D004271:DNA, Fungal / Q000378:metabolism*; D006657:Histones / Q000378:metabolism*; D008970:Molecular Weight; D010804:Physarum / Q000502:physiology*
chemical_list: D000596:Amino Acids; D004271:DNA, Fungal; D006657:Histones; C025301:histone H1 phosphate