Phosphorylation of histone H1 during the cell cycle of artichoke

Abstract. Histones have been extracted from tuber and cultured tuber explant material and separated by gel electrophoresis. Histone H1 is heterogenous with 3–4 components in addition to the widely recognized histone H1a and H1b. Using labelling procedures and alkaline phosphatase treatment, histone H1 has been shown to be phosphorylated on both serine and threonine residues and possibly other acid-labile linkages. Variations in histone H1 phosphorylation have been measured through the cell cycle and the evidence indicates enhanced phosphorylation occurring during the G2/M phase as in animal systems.