A mutation in the
            <i>Escherichia coli rho</i>
            gene that inhibits the N protein activity of phage λ

Das, Asis; Gottesman, Max E.; Wardwell, Judith; Trisler, P; Gottesman, Susan

doi:10.1073/pnas.80.18.5530

Cited by 35 publications

(41 citation statements)

References 31 publications

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“…Thus, these mutations can be considered as producing a "super-rho" phenotype. Further support for this view is provided by the observation that one of these rho mutations (rhoO26; also called nusDO26) (37,38) was shown to impede the antitermination activity of XN, specifically at rho-dependent terminators (8).…”

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confidence: 92%

Sequence and characterization of the bacteriophage T4 comC alpha gene product, a possible transcription antitermination factor

Sanson

Uzan

1992

J Bacteriol

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We have sequenced a 1,340-bp region of the bacteriophage T4 DNA spanning the comCa gene, a gene which has been implicated in transcription antitermination. We show that comCav, identified unambiguously by sequencing several missense and nonsense mutations within the gene, codes for an acidic polypeptide of 141 residues, with a predicted molecular weight of 16,680. We have identified its product on one-and two-dimensional gel systems and found that it migrates abnormally as a protein with a molecular weight of 22,000. One of the missense mutations (comCa803) is a glycine-to-arginine change, and the resulting protein exhibits a substantially faster electrophoretic mobility. The ComCa protein appears immediately after infection. Its rate of synthesis is maximum around 2 to 3 min postinfection (at 37°C) and then starts to decrease slowly. Some residual biosynthesis is still detectable during the late period of phage development.The notion that termination and antitermination mechanisms may be operating in bacteriophage T4 development initially came from the observation of a strong polarity on early transcription when infection is carried out in the absence of translation. In vivo experiments that used inhibitors of protein synthesis, as well as in vitro studies, have shown that this polarity is due to the action of the host transcription terminator p (2). The question of whether translation of phage RNA is required just to mask potential rho-dependent termination sites and/or to allow the synthesis of viral antitermination proteins could not be answered on the basis of experiments that used inhibitors of protein synthesis. Furthermore, analysis of this problem is complicated by the fact that many genes, transcribed by elongation of transcripts initiated at distal early promoters, are also transcribed from proximal promoters (the middle promoters) activated soon after infection (2,10,13,24,30,45,46).Another set of experiments showing the involvement of p in T4 development derives from the isolation of rho mutants unable to support growth of T4 wild-type phage. They were called tabC (5, 40, 41) or hdf (38). It has been suggested that the altered p proteins made in these mutants are insensitive to T4-induced antitermination factors (31, 38). Thus, these mutations can be considered as producing a "super-rho" phenotype. Further support for this view is provided by the observation that one of these rho mutations (rhoO26; also called nusDO26) (37,38) was shown to impede the antitermination activity of XN, specifically at rho-dependent terminators (8).Phage mutants able to grow on tabC/hdf rho host mutants were isolated. These compensatory mutations, called comC or goF, were mapped mainly in two places on the chromosome: upstream of gene 39, in a nonessential region of the T4 genome, and between genes 55 and e (5,7,17,36,38,42 involved in replication and in head assembly, respectively. Infection of a super-rho strain (hdf/rhoO26) with wild-type phage leads to an increased proportion of RNA ending at a specific site within g...

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confidence: 92%

Sequence and characterization of the bacteriophage T4 comC alpha gene product, a possible transcription antitermination factor

Sanson

Uzan

1992

J Bacteriol

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“…NusG expressed from a multicopy plasmid can rescue the NusD026 (because of a rho mutation) defect on Nantitermination Das et aL, 1983) suggesting that the NusD mutant lacks an efficient interaction with NusG in the N-antitermination complex. Indeed, an affinity-chromatography study showed that at higher temperatures where the wild type binds effectively, the Rho026 protein binds poorly to NusG .…”

Section: Nusg and Nusd (Rho)mentioning

confidence: 99%

Transcription antitermination: the λ paradigm updated

Friedman

Court²

1995

Molecular Microbiology

128

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“…lanes 3 and 4; 80% and 20% protection, respectively). Rho factor was not included in any of the footprinting reactions and was not necessary for protection of the n u t site RNA even though some mutations in the r h o gene interfere with antitermination by N at Rho-dependent terminators (Das et al 1983).…”

Section: Below)mentioning

confidence: 99%

The nut site of bacteriophage lambda is made of RNA and is bound by transcription antitermination factors on the surface of RNA polymerase.

Nodwell¹,

Greenblatt²

1991

Genes Dev.

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The boxA and boxB components of the k nut site are important for transcriptional antitermination by the phage N protein. We show here that boxA and boxB RNA in N-modified transcription complexes are inaccessible to ribonucleases and have altered sensitivity to dimethylsulfate. N and NusA suffice to weakly protect boxB, independently of boxA and other factors. However, efficient protection of the entire nut site from ribonucleases requires boxA and boxB, N, NusA, NusB, Sl0, and NusG. Mutations in RNA polymerase, which inhibit antitermination by N in vivo, disallow protection of the nut site during transcription in vitro; therefore, the surface of RNA polymerase must coordinate the formation of complexes containing the antitermination factors and nut site RNA.

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A mutation in the Escherichia coli rho gene that inhibits the N protein activity of phage λ

Cited by 35 publications

References 31 publications

Sequence and characterization of the bacteriophage T4 comC alpha gene product, a possible transcription antitermination factor

Sequence and characterization of the bacteriophage T4 comC alpha gene product, a possible transcription antitermination factor

Transcription antitermination: the λ paradigm updated

The nut site of bacteriophage lambda is made of RNA and is bound by transcription antitermination factors on the surface of RNA polymerase.

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