Characteristics of Purified recA Protein and the Regulation of Its Synthesis In Vivo

Abstract

The recA-gene product plays an indispensable role in homologous recombination in Escherichia coli. Recent studies have identified the recA-gene product as the X protein (Gudas and Mount 1977; McEntee 1977; Wabiko and Ogawa 1977), which is induced to accumulate when the SOS functions are provoked, e.g., λ prophage induction, induction of repair synthesis, and induction of mutation, as a result of UV or X-ray irradiation and of treatment with nalidixic acid or mitomycin C (Witkin 1976). However, it is still unclear whether the recA protein indirectly regulates the expression of genes related to these functions or whether the recA protein itself directly participates in these biochemical events. From this point of view, it seemed of interest to elucidate the function of recA protein and the regulation of its synthesis in cells.