Peculiarities of protein composition of nuclear matrix in some tumors and cultures of embryonic fibroblasts of the Chinese hamster

: The polypeptide pattern of the nuclear matrix of hepatomas differs significantly from that of intact liver. On the contrary, the polypeptide pattern of the nuclear matrix of Chinese hamster fibroblast culture is similar to that of tumour cells. In our studies the nuclear matrix was characterized by an increased content of polypeptides with Mr = 120,000-135,000 and 150,000-200,000 and a protein group with Mr of about 13,000 and lower. In metabolically active hepatomas and fibroblasts of Chinese hamster the content of high and low molecular weight components of the protein band triplet (Mr = = 65,000-70,000) in the logarithmic phase is decreased, while in hepatomas the content of the middle component of the triplet is increased. It is assumed that these peculiarities are due to the inhibition of differentiation and to an increased metabolic activity of the cells.