Control of gene expression in bacteriophage T7: Transcriptional controls

Ponta, Helmut; Rahmsdorf, Hans J.; Pai, S. H.; Hirsch‐Kauffmann, Monica; Herrlich, Peter; Schweiger, Manfred

doi:10.1007/bf00337463

Cited by 58 publications

(33 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The slightly reduced synthesis of early proteins in extracts from T7-infected F + cells (Table 2, Fig. 2 B) was probably due to the presence of some transcriptional inhibitor and some translational repressor [8,13]. For the same reason the synthesis of early proteins, such as T3 S-adenosylmethionine hydrolase, was also low in infected F -cells (Table 2).…”

Section: Enzymcmentioning

confidence: 95%

“…1 and 7). Because T7 induces regulatory proteins that interfere with the continued synthesis of early proteins [8,13], the influence of the F factor on T7 early synthesis was studied by infecting cells with a double mutant, defective in viral RNA polymerase and in protein kinase, which induces early proteins whose syntheses are continued for a longer time. When F-cells were infected with this mutant, early …”

Section: Duration Of T7 Early Protein Sjnthesis In Vivomentioning

confidence: 99%

“…This results in the induction of late T7 proteins [8]. It was interesting, therefore, to find out whether or not this synthesis of late proteins was also blocked by the episome mechanism.…”

Section: Fate Of Read-through Late Protein Synthesis In Vivomentioning

confidence: 99%

“…The only deficiency of synthesis in vitro was observed in extracts from F-cells late after T7 infection, which could not synthesize early T3 or T7 proteins due to the presence of T7 control proteins [8,13].…”

Section: Fate Of Read-through Late Protein Synthesis In Vivomentioning

confidence: 99%

See 3 more Smart Citations

The Sex-Factor-Dependent Exclusion of Coli Virus T7

et al. 1975

View full text Add to dashboard Cite

The cause of T7 exclusion by the F episome was investigated. Extracts from neither normal nor infected F + cells contained an inhibitor of gene expression in vitro. The protein synthesizing systems prepared in vitro from these cells supported T7 early and late protein synthesis with normal efficiency. The content of translational initiation factors in F-and F+ cells, both noninfected and infected, was almost identical. The episome-dependent block of T7 gene expression was observed only in intact cells and detailed kinetics of gene expression in vivo revealed a stop of all transcription and translation at or just before 11 min after T7 infection. The mechanism of Ff -dependent T7 exclusion involves both episomal and viral gene products. The data indicate that a T7-induced membrane alteration of the F+ cell membrane leads to cessation of T7 development as well as to the death of the host cell ('suicide').Investigations on the productive interaction between virus and host have yielded valuable information on the genetic controls of the virus. Abortive infection, on the other hand, should give insight into the physiology of the host as well as into the process of viral development. The virus T7 and its relatives (T3, $1, $11, W31, tau, and pasteurella virus H) infect abortively Escherichia coli cells carrying a sex factor [l -71. The study of the episomal interference with T7 development should reveal gene control mechanisms of T7 as well as the nature of the cellular alterations induced by the presence of the episome. We report here on the capacity of cell-free systems from noninfected and infected F-and F t cells to support T7 gene expression in vitro and on the course of T7 gene expression in F f cells in vivo. MATERIALS AND METHODS StraiiisBacterial strains are listed in Table 1. Purified initiation factors, salt-washed ribosomes and ribosomal subunits were prepared from Escherichia coli MRE600 (RNase I-).T7 arn193+K+ and T7 Cultivation of Cells M9 medium [8] at 30 "C.For all labeling experiments, cells were grown in Preparation of In it iation Factors10-1 cultures of strain JC 3272 (F-) and M176 (F') were harvested at A,,, = 0.8. Parallel cultures were infected with T7 wild-type at a multiplicity of infection of 10. The surviving cells at 3 min past infection were 0.3-1.5 %. The wet weight of cells was 12-15 g each. The cells (each type of cells separately) were suspended in 25 ml buffer A (0.01 M Tris-HC1, pH 7.9, 0.01 M MgCl,, 0.06 M NH,Cl, 1 mM dithiothreitol) and were ruptured by a French pressure cell at 14000 lb/in2 (96.5 MPa) (Aminco). 50 pg DNase was added. The debris was removed by centrifugation at 20000 x g for 60 min and the ribosomes were pelleted at 175000 x g for 5 h. Each ribosome preparation was suspended in 40ml ribosome washing buffer (0.1 M Tris-HC1, pH 7.9; 0.01 M magnesium acetate, 0.05 M KCI, 1 M NH,CI, 1 mM dithiothreitol) and stirrcd at 0 'C for 12 h. Thc washed ribosomes were pelleted and the procedure repeated once. The ribosome-free supernatants were combined and precipitated with (...

show abstract

Section: Enzymcmentioning

confidence: 95%

Section: Duration Of T7 Early Protein Sjnthesis In Vivomentioning

confidence: 99%

“…This results in the induction of late T7 proteins [8]. It was interesting, therefore, to find out whether or not this synthesis of late proteins was also blocked by the episome mechanism.…”

Section: Fate Of Read-through Late Protein Synthesis In Vivomentioning

confidence: 99%

Section: Fate Of Read-through Late Protein Synthesis In Vivomentioning

confidence: 99%

See 2 more Smart Citations

The Sex-Factor-Dependent Exclusion of Coli Virus T7

et al. 1975

View full text Add to dashboard Cite

show abstract

“…We searched for a similar activity in BA14-infected cells using the method of Ponta et al (1974) . Phage-directed protein kinase synthesis.…”

Section: Ba14-directed Protein Kinase Activitymentioning

confidence: 99%

Coliphage BA14: a New Relative of Phage T7

Mertens

Hausmann

1982

Journal of General Virology

View full text Add to dashboard Cite

SUMMARYColiphage BA14 was isolated from sewage and shown to be related to phages T7 and T3. It is similar to T3 in that it directs the synthesis of an S-adenosylmethionine-cleaving enzyme (SAMase) early upon infection. However, it differs from all other known T7-related coliphages by the inability of its RNA polymerase (gene 1 product) to transcribe T7 DNA or T3 DNA. BA14, T7 and T3 also show marked differences in ~ autoradiographic patterns of their gel-electrophoreticalty separated 35S-labelled intracellular phage proteins, restriction endonuclease HpaI cleavage patterns of their DNAs, and serological specificities of their infectious particles. Other distinctive features became apparent upon simultaneous mixed infection with BA14 and T7 or T3: inability of BA14 to produce genetic recombinants with either T7 or T3; lack of functional complementation between amber mutants of BA14 and T7 or T3; mutual exclusion and depression of the burst size of the mixedly infected cells.

show abstract

Reproduction of Large Virulent Bacteriophages

Mathews¹

1977

Comprehensive Virology

View full text Add to dashboard Cite

Control of gene expression in bacteriophage T7: Transcriptional controls

Cited by 58 publications

References 20 publications

The Sex-Factor-Dependent Exclusion of Coli Virus T7

The Sex-Factor-Dependent Exclusion of Coli Virus T7

Coliphage BA14: a New Relative of Phage T7

Reproduction of Large Virulent Bacteriophages

Contact Info

Product

Resources

About