New RNA polymerase from Escherichia coli infected with bacteriophage T7

Temperature-shift analysis of bacteriophage phi 29 gene expression in Bacillus amyloliquefaciens

Temperature shift-up experiments with conditional lethal mutants of Bacillus phage phi29 have allowed placement of early, middle, and late functions on the linear phi29 genetic map Most of the phi29 cistrons are late and are found at the ends of the map.

Properties of a soluble DNA polymerase isolated from Rous sarcoma virus

The DNA polymerase of the Prague strain of Rous sarcoma virus of subgroup C and of the Schmidt-Ruppin strain of subgroup A has been solubilized. DNA polymerase purified by sucrose gradient sedimentation and chromatography on DEAE-cellulose represented less than 2% of the soluble [(14)C]protein of the virus. The enzyme was separated from 90% of the viral glycoprotein; it is probably different from the viral group-specific antigen. The sedimentation coefficient (s(20, w)) of the soluble DNA polymerase was 8 S before, and 6 S after, incubation with pancreatic RNase. The molecular weight of the 8S DNA polymerase was estimated to be about 170,000, and that of the 6S DNA polymerase to be about 110,000. Purified DNA polymerase had a high activity with 60-70S viral RNA or salmon DNA as template, but it had a low activity with heat-dissociated 60-70S RNA, influenza virus RNA, or the RNA of tobacco mosaic virus as template. Neither the 8S nor the 6S DNA polymerase had endogenous template activity. The DNA-dependent and the RNA-dependent DNA polymerase activities of the Prague strain coincided in sucrose gradients, both in the 8S and the 6S form. It is concluded that the RNA-dependent and the DNA-dependent DNA polymerase activities of the avian tumor viruses are probably due to the same enzyme.