SYNTHESIS OF BACTERIOPHAGE MU PROTEINS INVITRO

DNA extracted from purified Mu phage directs the synthesis of at least 12 unique proteins in a DNA-dependent protein-synthesizing system derived from Escherichia coli. A comparison of the proteins synthesized in vitro from various DNA templates, including Mu mutants, λpMu hybrid phages, or specific Mu fragments generated by digestion with restriction enzymes, has allowed us to assign several of the proteins to specific genes. Assuming that the products made in vitro are the same as those synthesized in vivo, our results lead to the following interpretations. (a) A gene in the immunity region codes a protein of 24,000 daltons which may be the phage repressor; (b) gene A product is a polypeptide of 70,000 daltons; a protein of 64,000 daltons in coded by gene M or N; (c) gene B (or Bu) product is 33,000 daltons and is synthesized in large quantities; (d) the product of gene R is 41,500 daltons; (e) two polypeptides of 53,000 and 35,000 daltons, respectively, may be coded by genes between E and L; (f) a gene between B and C directs the sythesis of a protein of 14,000 daltons; and (g) a major protein is coded by DNA in the G-loop or β region. © 1978.