Effect of high mobility group proteins 14 and 17 on the structural and transcriptional properties of acetylated complete and H2A.H2B-deficient nucleosomal cores.

Acetylation of H2A.H2B-deficient nucleosomal cores, like that of the complete particles, causes a substantial increase in the efficiency of the particles as in vitro transcription templates. Binding of the high mobility group proteins 14 and 17 (HMG 14/17) to chemically acetylated nucleosomal particles, both complete nucleosomal cores and those lacking one of the two H2A.H2B dimers, is accompanied by a small structural stabilization. The affinity of HMG 14/17 for the nucleosomal cores is not affected by acetylation of the particles. With acetylated complete and H2A.H2B-deficient cores, the binding of HMG 14/17 does not cause any significant change in the levels of RNA synthesis, which is compatible with the presence of these proteins in transcriptionally active nucleosomes.