Elongation factor NusG interacts with termination factor rho to regulate termination and antitermination of transcription.

Li, Joyce; Mason, Stephen W.; Greenblatt, Jack

doi:10.1101/gad.7.1.161

Cited by 120 publications

(142 citation statements)

References 66 publications

(80 reference statements)

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“…A plausible model for resistance to Rho-mediated termination is that stable incorporation of NusG into an antitermination complex precludes its ability to interact with Rho or to stabilize Rho-RNA and/or Rho-polymerase contacts, whether by physical interference or conformational alteration. Whatever the explanation, this unusual protein may be the unifying factor for understanding both termination and antitermination, as suggested previously by Sullivan and Gottesman (1992) and Li etal. (1993).…”

Section: Elongation Complexes Termination Antitermination and Nusgmentioning

confidence: 54%

Rho and RNA: models for recognition and response

Platt

1994

Molecular Microbiology

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SummaryEscherichia coli Rho factor Is required for termination of transcription at certain sites by RNA potymerase. Binding to unstructured cytosine^ontaining RNA target sites, subsequent RNA-dependent ATP hydrolysis, and an RNA-DNA helicase activity that presumably facilitates termination, are considered essential for Rho function. Yet the RNA recognition elements have remained elusive, the parameters relating RNA binding to ATPase activation have been obscure, and the mechanistic steps that integrate Rho's characteristics with its termination function in vitro and in vivo have been iargely undefined. Recent work offers new insights into these interactions with results that are both surprising and satisfying in the context of Rho's emerging structure. These include the requirements for binding and ATPase activation by a variety of RNA substrates, dynamic analyses of Rho tracking, heiicase and termination activity, and the participation of a new factor (NusG) that interacts with Rho. Models for Rho function are considered in the light of these recent revelations.

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Section: Elongation Complexes Termination Antitermination and Nusgmentioning

confidence: 54%

Rho and RNA: models for recognition and response

Platt

1994

Molecular Microbiology

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“…In addition, an invariant glycine residue in the motif was found in all proteins except yeast Spt5. Thus, p160 is related to NusG, which is a member of a class of essential transcription elongation factors that have been implicated in a variety of cellular and viral termination and antitermination processes (Li et al 1992(Li et al , 1993Sullivan and Gottesman 1992;Burns and Richardson 1995;Mogridge et al 1995). A recent study has shown that E. coli NusG stimulates the rate of transcription elongation both in vivo and in The positions of the acidic domain at the amino terminus, highly conserved regions, and the carboxy-terminal repeats are marked by closed boxes.…”

Section: Dsif Can Stimulate Transcription Elongation Under Certain Comentioning

confidence: 99%

DSIF, a novel transcription elongation factor that regulates RNA polymerase II processivity, is composed of human Spt4 and Spt5 homologs

Wada

Takagi

Yamaguchi

et al. 1998

Genes & Development

658

707

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We report the identification of a transcription elongation factor from HeLa cell nuclear extracts that causes pausing of RNA polymerase II (Pol II) in conjunction with the transcription inhibitor 5,6-dichloro-1-␤-D-ribofuranosylbenzimidazole (DRB). This factor, termed DRB sensitivity-inducing factor (DSIF), is also required for transcription inhibition by H8. DSIF has been purified and is composed of 160-kD (p160) and 14-kD (p14) subunits. Isolation of a cDNA encoding DSIF p160 shows it to be a homolog of the Saccharomyces cerevisiae transcription factor Spt5. Recombinant Supt4h protein, the human homolog of yeast Spt4, is functionally equivalent to DSIF p14, indicating that DSIF is composed of the human homologs of Spt4 and Spt5. In addition to its negative role in elongation, DSIF is able to stimulate the rate of elongation by RNA Pol II in a reaction containing limiting concentrations of ribonucleoside triphosphates. A role for DSIF in transcription elongation is further supported by the fact that p160 has a region homologous to the bacterial elongation factor NusG. The combination of biochemical studies on DSIF and genetic analysis of Spt4 and Spt5 in yeast, also in this issue, indicates that DSIF associates with RNA Pol II and regulates its processivity in vitro and in vivo.

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“…Crystallographic analysis of a Rho-RNA structure shows that Rho binds Ϸ60 nt of transcript, which circles the RNA-binding domain of the Rho hexamer and penetrates into the translocase active center of Rho, oriented such that Rho can track in a 5Ј-3Ј direction along the RNA (3). Although Rho is very unlikely to contact RNA in the region of the RNA͞DNA hybrid in the transcription complex directly, a ''helicase'' activity could result from translocation that effectively pulls RNA from the complex, requiring that Rho be braced against RNAP at some undefined interaction site or possibly through an intermediary protein like NusG, which is known to bind both Rho and RNAP core (16).…”

Section: Heteroduplex Dna In the Transcription Bubble Region Also Inhmentioning

confidence: 99%

Role of DNA bubble rewinding in enzymatic transcription termination

Park

Roberts

2006

Proc. Natl. Acad. Sci. U.S.A.

114

117

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By using DNA heteroduplexes that inhibit rewinding of the upstream part of the transcription bubble, we show that transcript release in termination by the enzymes Mfd and Rho is facilitated by reannealing of DNA in the upstream region of the transcription bubble, as is also true for termination by intrinsic terminators. We also show that, like Mfd, the Rho termination factor promotes forward translocation of RNA polymerase. These results support termination models in which external forces imposed on nucleic acids induce concerted rewinding of DNA and unwinding of the DNA͞RNA hybrid, possibly accompanied by forward translocation of RNA polymerase, leading to transcription complex dissociation.RNA polymerase ͉ Mfd protein ͉ Rho termination factor T ermination of transcription and the release of RNA polymerase (RNAP) from its templating complex with DNA are essential for providing a boundary for gene expression and removing stalled enzymes that may obstruct gene expression and replication. Three mechanisms are known that cause the otherwise notably stable transcription complex of Escherichia coli RNAP to dissociate. These mechanisms are (i) the intrinsic terminator, consisting of nucleic acid structures that interact with RNAP (1), (ii) the termination factor Rho, an RNAdependent ATPase and RNA ''helicase'' (or, more accurately, RNA translocase) that acts by binding the emerging transcript and (presumably) RNAP (2, 3), and (iii) Mfd, an ATPdependent DNA translocase that acts on RNAP and DNA upstream of the transcription bubble (4-6) ( Fig. 1). [The replication fork apparatus could contain a fourth mechanism that removes obstructing transcription complexes (7).] Understanding these termination pathways may reveal important aspects of transcription complex stability, as well as the nature of regulation that acts through antitermination.Two classes of models of termination describe how nucleic acids could move relative to the enzyme such that the RNA becomes weakly held and can dissociate, leading to RNAP dissociation. The first class of models (''mechanical models''), illustrated in Fig. 2, proposes that rewinding of the upstream boundary of the transcription bubble is coupled with unwinding of the RNA͞DNA hybrid within the enclosing structure of the enzyme (Fig. 2 B and C). In one mechanical model (Fig. 2B), the enzyme translocates forward without RNA synthesis, retaining protein-nucleic acid contacts of the elongation complex (8, 9); in another (Fig. 2C), the transcription bubble collapses within the channel as the hybrid unwinds, without enzyme translocation. The second class of models (''allosteric'') is less defined but proposes that long-range conformational changes in RNAP induced by some element of the terminator (e.g., the RNA hairpin or activities of the enzymatic terminators) destabilize the enzyme-nucleic acid contacts and lead to complex collapse (10).One apparent similarity among intrinsic and enzymatic terminators favoring mechanical models is that all three involve forces exerted on upstream nucleic a...

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Elongation factor NusG interacts with termination factor rho to regulate termination and antitermination of transcription.

Cited by 120 publications

References 66 publications

Rho and RNA: models for recognition and response

Rho and RNA: models for recognition and response

DSIF, a novel transcription elongation factor that regulates RNA polymerase II processivity, is composed of human Spt4 and Spt5 homologs

Role of DNA bubble rewinding in enzymatic transcription termination

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