Association of bacteriophage proteins and RNA in E.,coli infected with MS2

Infection of E.,coli with the RNA bacteriophage MS2 leads to the synthesis of three phage-specific proteins: phage coat protein, "maturation" protein, and RNA synthetase, which can be separated and quantitated by gel electrophoresis (Nathans, Oeschger, Eggen and Shimura, 1966;,Vinuela, Algranati and Ochoa, 1967;,Eggen, Oeschger and Nathans, 1967). Each of these proteins might be expected to interact with phage RNA in the course of phage development. In the case of coat protein two kinds of in,vitro complexes have been described with RNA extracted from purified phage particles. One of these results from the binding of a small number of coat protein molecules (Capecchi and Gussin, 1965;,Sugiyama, Hebert and Hartman, 1967), and the other resembles intact virions but is non-infectious (Sugiyama et,al., 1967). In the case of MS2 RNA synthetase, the sedimentation rate of this enzyme in lysates of infected cells suggests that it may be bound to RNA or a ribonucleoprotein particle (Weissman, Simon, Borst and Ochoa, 1963). The "maturation" protein (Lodish and Zinder, 1965;,Heisenberg, 1966;,Argetsinger and Gussin, 1966) has been shown to be present in normal phage particles in small amount (Nathans et,al., 1966), and it is possible that a complex between this protein and phage RNA is an intermediate in phage assembly. In this paper we report the detection in extracts of E.,coli infected with MS2 of a complex or complexes involving RNA and each of the three phage-specific proteins.