Maximal binding levels of an H1 histone gene-specific factor in S-phase correlate with maximal H1 gene transcription

Levels of trans-acting factor (H1-SF) binding to the histone H1 gene-specific motif (5'-AAACACA-3' [L. S. Coles and J. R. E. Wells, Nucleic Acids Res. 13:585-594, 1985]) increase 12-fold from G1 to S-phase in synchronized cells and decrease again in G2 phase of the cell cycle. Since the H1 element is required for S-phase expression of H1 genes (S. Dalton and J. R. E. Wells, EMBO J. 7:49-56, 1988), it is likely that the increased levels of H1-SF binding component play an important role in S-phase regulation of H1 gene transcription.