HMG‐like proteins of <i>Physarum polycephalum:</i> Association with the transcriptionally active chromatin

Abstract

HMG‐like proteins were isolated from nuclei of the acellular slime mold Physarum polycephalum . These proteins represented 0.6 ± 0.2% of nuclear proteins and approx. 6% of DNA by weight. Polyacrylamide gel electrphoresis demonstrated the presence of 3 major proteins, designated HMG‐1P, HMG‐2P and HMG‐14/17P. None of these proteins comigrated with any of the calf thymus HMGs. Physarum HMG‐like proteins were found to be preferentially associated with transcriptionally active chromatin fraction, as well as being released from nuclei by light DNase I digestion. In contrast, the content of histone H1 was significantly lower in active than in inactive chromatin fraction.