Studies on the position of nonhistone chromatin protein (LMG160) in the chromatin fractions of rat liver nuclei

Nonhistone chromosomal proteins are a set of heterogenous chromatin proteins which play different functions dependent on the cell type. A group of these proteins with a high molecular weight and low mobility on the gel electrophoresis, called LMG proteins, has been the subject of many workers. We have recently isolated a fraction of these proteins from rat liver nuclei, with a molecular weight of 160 KDa and named HMG160. In this study the position of this purified protein in different fractions of chromatin has been studied. After brief digestion of rat liver chromatin with MNase, chromatin fractions S1 and S2 were prepared and analyzed by gel electrophoresis and imminobloting techniques. The results show that the protein LMG160 has higher affinity to di- and oligonucleosomes rather than to mononucleosomes. This implies that LMG160 preferentially binds to bulk chromatin and may have a role in chromatin inactivation which demands further investigation.