Competence of membrane-bound T4rII DNA for in vitro "late" mRNA transcription

In vitro transcription of phage T4 late genes on purified DNA by partially purified RNA polymerase from T4-infected Escherichia coli b cells

RNA polymerase was purified from 'late' phage T4-infected Escherichia coli B cells by DNA-cellulose affinity chromatography and high salt agarose filtration. The DNA-cellulose-purified RNA polymerase preparation contained T4-coded DNA endonuclease activity and several proteins, some with sizes comparable with the known T4 maturation factors, essential for late RNA synthesis. Some of these proteins, and the DNA endonuclease utilizing native, parental T4 DNA and supercoiled phi X 174 DNA as substrates, were partially separated from the RNA polymerase as a complex during agarose filtration. In vitro RNA was made by the DNA-cellulose-purified RNA polymerase using native, parental T4 DNA as template. About 26% of the in vitro RNA was transcribed from the DNA r-strand; 75% from the same r-strand region as in vivo late after infection. Both the abundancy and specificity of the in vitro r-strand transcription were markedly reduced after agarose filtration of the enzyme. Addition of the proteins separated from the RNA polymerase during agarose filtration caused a restoration of in vitro r-strand transcription abundance, but not its specificity. These results show that partially purified RNA polymerase from T4-infected E. coli B cells was able to transcribe late T4 genes in vitro with some abundancy and specificity on purified, parental T4 DNA, but further purification of the enzyme caused an irreversible reduction of this ability.

DNA-RNA polymerase complexes associated with the membrane from bacteriophage T2- or T4-infected Escherichia coli. I. General properties

Properties of DNA-RNA polymerase complexes, apparently bound to a fraction of the cell membrane of bacteriophage T2- or T4-infected Escherichia coli, are described. Evidence is presented to show that the complexes initiate the asymmetric synthesis of RNA, and release the finished product. The transcription capacity per unit of beta' + beta was 10 times higher at 6 min than at 30 min after infection.

DNA-RNA polymerase complexes associated with the membrane from bacteriophage T2- or T4-infected Escherichia coli. II. A comparison of in vitro RNA with the in vivo RNA products

Membrane preparations, containing DNA-RNA polymerase from bacteriophage T2- or T4-infected Escherichia coli, caused the asymmetric synthesis of RNA classes similar to those produced sequentially in vivo: 1, Pre-early RNA was formed when a membrane preparation was isolated 1 min after infection. 2, Pre-early and delayed early RNA, in roughly the same proportion as that obtained in vivo, was synthesized by a preparation obtained 6 min after infection. 3, Pre-early, delayed early and late genes were transcribed by preparations isolated from cells during the late period of infection. In late preparations, however, less late and more pre-early RNA was usually synthesized in vitro than that obtained in vivo. Late RNA was not synthesized when a phage T4 mutant defective in either gene 33 or gene 55 was used. Evidence is presented to show that late RNA synthesis cannot solely be accounted for from the completion of already initiated chains.

Analysis of expression of the rII gene function of bacteriophage T4

Temperature-sensitive (ts) mutants of the T4 phage rII gene were islated and used in temperature shift experiments that revelaed two different expressions for the normal rII (rII+) gene function in vivo: (i) an early expression (0 to 12 min postinfection at 30 C) that prevents restriction of T4 growth in Escherichia coli hosts lysogenic for gamma phage, and (ii) a later expression (12 to 18 min postinfection at 30 C) that results in restriction of T4 growth when the phage DNA ligase (gene 30) is missing. The earlier expression appeared to coincide with the period of synthesis of the protein product of the T4 rIIA cistron, whereas the later expression occurred after rIIA protein synthesis had stopped. The synthesis of the protein product of the rIIB cistron continues for several minutes after rIIA protein synthesis ceases (O'Farrell and Gold, 1973). The two rII+ gene expressions might require different molar ratios of the rIIA and rIIB proteins. It is possible that the separate expressions of rII+ gene function are manifestations of different associations between the two rII proteins and other T4-induced proteins that are synthesized or activated at different times after phage infection.