Synthesis of a Class of DNA‐Binding Proteins in Synchronized Untransformed and Virus‐Transformed Cells

Abstract

The synthesis of a class of proteins with affinity for denatured DNA was studied in synchronized cultures of the established hamster fibroblast line NIL-1 and its virus-transformed derivative NIL-1-hamster sarcoma virus. Synthesis of a DNA-binding protein (P6, MW 50,000) in synchronized untransformed NIL-1 cells follows a pattern different from that observed in the transformed cells. The protein is low in stationary cultures of NIL-1 and NIL-1-hamster sarcoma virus but increases after the cells are stimulated to grow, although the time of maximal P6 synthesis relative to cellular DNA synthesis is different in NIL-1 and NIL-1-hamster sarcoma virus. The pattern of synthesis of 2 other DNA-binding proteins (P7 and P8'') is essentially identical in synchronized untransformed and transformed cells. P7 is low in resting cultures of both types of cells, but greatly increases early after the cells are stimulated to divide, while P8'' is high in stationary cultures and decreases slightly after the initiatio of cellular DNA synthesis has occurred.