Influence of nonhistone chromatin protein HMG-1 on the enzymatic digestion of purified DNA

摘要

The effect of chicken erythrocyte High Nobility Group protein 1 (HMG-1) on the enzymatic hydrolysis of purified double-stranded and single-stranded bacteriophage lambda DNA was studied. HMG-1 was found to inhibit the digestion of single- end double-stranded DNA by S1 nuclease and DNase I, respectively. HMG-1 increased the rate of hydrolysis of double-stranded DNA by micrococcal nuclease, particularly at low HMG-1/DNA ratios, and had little effect on the hydrolysis of single-stranded DNA by micrococcal nuclease, even at high HMG-1/DNA ratios. We also present a semi-quantitative estimate that HMG-1 and HMG-2 occur in chromatin from rapidly dividing, cultured rat hepatoma cells at about 8 times the level that they occur in adult rat liver chromatin.