RESUMO
Twenty-three (14)C-labeled phage phi29-specific proteins in lysates of UV-irradiated Bacillus subtilis have been resolved by sodium dodecyl sulfate polyacrylamide gel electrophoresis and identified by autoradiography. Included in this group of proteins are the six major structural proteins of the virion. Analysis of the temporal sequence of viral protein synthesis indicates that three groups of proteins can be identified by time of appearance, beginning at 2 to 4, 4 to 6, or 8 to 10 min after infection, respectively. These proteins account for approximately 90% of the coding capacity of the phi29 genome.
Assuntos
Bacillus subtilis/metabolismo , Bacteriófagos/metabolismo , Proteínas Virais/biossíntese , Autorradiografia , Bacillus subtilis/efeitos da radiação , Radioisótopos de Carbono , Eletroforese em Gel de Poliacrilamida , Microscopia Eletrônica , Peso Molecular , Efeitos da Radiação , Dodecilsulfato de Sódio , Fatores de Tempo , Raios Ultravioleta , Proteínas Virais/isolamento & purificaçãoRESUMO
The synthesis of ribonucleic acid (RNA) during development of the virulent Bacillus subtilis bacteriophage phi29 has been analyzed. Transcription of host deoxyribonucleic acid (DNA) continues at the preinfection rate throughout the latent period of viral growth. RNA-DNA hybridization was used to show that host messenger RNA synthesis continues late into the phage lytic cycle. Amino acid-labeling experiments show that this RNA is continuously used to produce protein. Ribosomal RNA production is not inhibited by phage infection. Small quantities of phage-specific RNA first appear between min 6 and 9 after infection. This RNA is made exclusively from one of the phi29 DNA strands. At 12 min postinfection, when phage DNA replication commences, large quantities of viral RNA start to be synthesized. This RNA appears to be transcribed from both strands of phi29 DNA. Studies with rifamycin and rifamycin-resistant host strains showed that the production of all phage phi29-specific RNA requires those components of the host RNA polymerase which are sensitive to this antibiotic. Thus, phage phi29 does not stop transcription of host DNA and may produce only one element for regulation of transcription of its own DNA. These findings may reflect the limited amount of genetic information carried by this phage.