NusG overexpression inhibits Rho‐dependent termination in <i>Escherichia coli</i>

Burova, Elena; Gottesman, Max E.

doi:10.1111/j.1365-2958.1995.mmi_17040633.x

Cited by 23 publications

(19 citation statements)

References 27 publications

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“…5 Although the mechanism of the bacteriophage growth exclusion has not yet been elucidated, these Rho factors cause transcription of the cro gene DNA template to be terminated at sites that precede those used with wild-type Rho alone but identical to those used when NusG is also present. 4 Thus, this mutation has made the Rho factor less dependent on NusG, which is consistent with its partial termination activity after NusG depletion in vivo (38).…”

Section: Functional Changes Involving Non-conserved Residuessupporting

confidence: 51%

Structural Organization of Transcription Termination Factor Rho

Richardson

1996

Journal of Biological Chemistry

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Escherichia coli has two known modes for termination of RNA transcription (1-4). One is intrinsic to the function of RNA polymerase, which can spontaneously terminate transcription in response to certain, limited sequences. The other mode is dependent upon the action of an essential protein factor called Rho and occurs at sequences that are specific for its function but that are less constrained than the sequences for intrinsic termination.Rho protein functions as a hexamer of a single polypeptide chain with 419 residues, which is the product of the rho gene (5). It is an RNA-binding protein with the capacity to hydrolyze ATP and other nucleoside triphosphates. Rho acts to cause termination by first binding to a site on the nascent transcript and by subsequently using its ATP hydrolysis activity as a source of energy to mediate dissociation of the transcript from RNA polymerase and the DNA template (6). In the cell, the ability of Rho to act at several terminators is dependent upon the presence of an essential 21-kDa protein called NusG (7) that binds both RNA polymerase and Rho itself (8). In vitro the dependence on NusG became apparent only at proximal terminators (at sites Ͻ300 base pairs from the promoter) and under conditions when the RNA molecules are being elongated at the in vivo rate of ϳ40 -50 nucleotides/s (9). The requirement for NusG when RNA chain growth is fast suggests that the NusG is acting to overcome a kinetic limitation of Rho to act alone, perhaps through mediating earlier access to the nascent RNA by the formation of a complex of Rho with RNA polymerase (10).The mechanism of how Rho acts to dissociate the transcription complex is unknown. One important approach to elucidating how interactions with RNA mediate termination of transcription is to determine the structure of the protein. Until a good crystal structure becomes available the properties of its structure will have to be inferred from other, less direct methods, such as biochemical characterization of the protein, phylogenetic comparative analyses, and the functional properties of mutants with known amino acid changes. This review summarizes our current understanding of the structure and function of transcription termination factor Rho based on these indirect approaches.

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Section: Functional Changes Involving Non-conserved Residuessupporting

confidence: 51%

Structural Organization of Transcription Termination Factor Rho

Richardson

1996

Journal of Biological Chemistry

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“…UpxYs prevent premature transcriptional termination of the respective loci. NusG has roles in both transcriptional termination and antitermination (6,7,19,22). Based on the phenotypes and transcriptional analyses of the upxY deletion mutants and the activity of the well-characterized NusG SP RfaH, we predicted that the UpxYs function to prevent premature transcriptional termination of their respective PS operon.…”

Section: Resultsmentioning

confidence: 99%

A Family of Transcriptional Antitermination Factors Necessary for Synthesis of the Capsular Polysaccharides of Bacteroides fragilis

2009

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A single strain of Bacteroides fragilis synthesizes eight distinct capsular polysaccharides, designated PSA to PSH. These polysaccharides are synthesized by-products encoded by eight separate polysaccharide biosynthesis loci. The genetic architecture of each of these eight loci is similar, including the fact that the first gene of each locus is a paralog of the first gene of each of the other PS loci. These proteins are designated the UpxY family, where x is replaced by a to h, depending upon the polysaccharide locus from which it is produced. Mutational analysis of three separate upxY genes demonstrated that they are necessary and specific for transcription of their respective polysaccharide biosynthesis operon and that they function in trans. Transcriptional reporter constructs, reverse transcriptase PCR, and deletion analysis demonstrated that the UpxYs do not affect initiation of transcription, but rather prevent premature transcriptional termination within the 5 untranslated region between the promoter and the upxY gene. The UpxYs have conserved motifs that are present in NusG and NusG-like proteins. Mutation of two conserved residues within the conserved KOW motif abrogated UpaY activity, further confirming that these proteins belong to the NusG-like (NusG SP ) family. Alignment of highly similar UpxYs led to the identification of a small region of these proteins predicted to confer specificity for their respective loci. Construction of an upaY-upeY hybrid that produced a protein in which a 17-amino-acid segment of UpaY was changed to that of UpeY altered UpaY's specificity, as it was now able to function in transcriptional antitermination of the PSE biosynthesis operon.

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“…Inhibition of Rho function was also demonstrated by the effect of yaeO on lacZ separated from P L by Rho-dependent terminator t L1 or by t L1 and the early left operon Rhoindependent terminator t I (Burova and Gottesman, 1995). In either case, expression of yaeO by P R (pSEB39) led to 1.8 Ϯ 0.12 times higher lacZ expression (Table 2, experiment 1).…”

Section: Fig 3 Sds-page Of Ni 2þmentioning

confidence: 96%

“…In addition, the factor NusG stimulates termination at many sites in vivo and, to a lesser extent, in vitro. By facilitating Rho-RNA polymerase interaction, perhaps by bridging Rho to RNA polymerase, NusG helps to form an efficient termination complex (Li et al, 1993;Platt, 1994;Burova and Gottesman, 1995).…”

Section: Introductionmentioning

confidence: 99%

An Escherichia coli gene (yaeO ) suppresses temperature‐sensitive mutations in essential genes by modulating Rho‐dependent transcription termination

Pichoff

Alibaud

Guédant

et al. 1998

Molecular Microbiology

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SummaryAn extragenic multicopy suppressor of the cell division inhibition caused by a MalE-MinE fusion protein in Escherichia coli has been mapped and identified as yaeO, one of the two short open reading frames (ORFs) of an operon located at 4.6 min. Overexpressed yaeO also suppressed some temperature-sensitive mutations in division genes ftsA and ftsQ, in chaperone gene groEL and in co-chaperone gene grpE. Gene yaeO, whose expression is regulated by growth rate, codes for a 9 kDa acidic protein with no obvious resemblance to other proteins. Transcription termination protein Rho co-purified with a histidine-tagged derivative of YaeO protein on Ni 2þ -NTA agarose columns in a manner that suggested direct YaeO-Rho interaction. In vivo, yaeO expression reduced termination at rho-dependent bacteriophage terminator t L1 and at the terminator of autogenously regulated gene rho. The suppression of temperature-sensitive phenotypes was a consequence of anti-termination, as it could be mimicked by a P rho ::Tn10 mutation that reduces the expression and activity of gene rho. Our data indicate that the suppression is not caused by overexpression of the mutated genes, but presumably by indirect stabilization of the mutated proteins.

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NusG overexpression inhibits Rho‐dependent termination in Escherichia coli

Cited by 23 publications

References 27 publications

Structural Organization of Transcription Termination Factor Rho

Structural Organization of Transcription Termination Factor Rho

A Family of Transcriptional Antitermination Factors Necessary for Synthesis of the Capsular Polysaccharides of Bacteroides fragilis

An Escherichia coli gene (yaeO ) suppresses temperature‐sensitive mutations in essential genes by modulating Rho‐dependent transcription termination

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