Transcription antitermination in vitro by lambda N gene product: Requirement for a phage nut site and the products of host nusA, nusB, and nusE genes

Das, Asis; Wolska, Krystyna I.

doi:10.1016/0092-8674(84)90537-3

Cited by 81 publications

(77 citation statements)

References 43 publications

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“…Because tat shares structural and functional features with bacteriophage k N antiterminator (Franklin and Bennett 1979), which also does not bind to its N-utilization (nut) site, but does bind to a transcription complex that pauses at the n u t site (Barik et al 1987), it is possible that tat will bind only to its target sequence in the presence of RNA polymerase II and associated proteins. In a further analogy with HIV, the n u t site forms an RNA stem-loop, and a single nucleotide substitution in the loop abolishes antitermination by N (Rosenberg et al 1978;Salstrom and Szybalski 1978;Das and Wolska 1984).…”

Section: Discussionmentioning

confidence: 99%

Structure, sequence, and position of the stem-loop in tar determine transcriptional elongation by tat through the HIV-1 long terminal repeat.

Selby¹,

Bain²,

Luciw³

et al. 1989

Genes Dev.

359

349

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The human immunodeficiency virus (HIV-1)-encoded trans-activator (tat) increases HIV gene expression and replication. Previously, we demonstrated that tat facilitates elongation of transcription through the HIV-1 long terminal repeat (LTR) and that short transcripts corresponding to prematurely terminated RNA are released and accumulate in the absence of tat. Here, using a transient expression assay, we tested clustered and compensatory mutations, as wall as 3' deletions, in the trans-acting responsive region (tar) and observed that the primary sequence in the loop and secondary structure in the stem of the stem-loop in tar are required for trans-activation by tat. Insertions in the 5' region of tar revealed that tar must be near the site of HIV-1 initiation of transcription for trans-activation by tat. Deletions (3') and an insertion in tar demonstrated that an intact stem-loop is required for the recovery of prematurely terminated transcripts. Short and full-length transcripts were observed also with HIV type 2 (HIV-2) in the absence and presence of tat, respectively. We conclude that an intact stem-loop in tar is essential for trans-activation by tat and that initiation of transcription by HIV-1 promoter factors and elongation of transcription by tat are coupled.

show abstract

Section: Discussionmentioning

confidence: 99%

Structure, sequence, and position of the stem-loop in tar determine transcriptional elongation by tat through the HIV-1 long terminal repeat.

Selby¹,

Bain²,

Luciw³

et al. 1989

Genes Dev.

359

349

View full text Add to dashboard Cite

show abstract

“…Although NusB is not an integral ribosomal protein, it does influence translation, as shown by the observation that nusB mutants have slowed translation rates relative to wild type (Taura et aL, 1992), and is associated with ribosomes following high-salt wash (Das and Wolska, 1984). NusB null mutants have the interesting property of being cold sensitive for growth (Taura et aL, 1992;Georgopoulos et aL, 1980).…”

Section: Nusb and Nusementioning

confidence: 99%

“…Nonsense mutations uncouple translation from transcription, allowing unimpeded access of Rho to the paused polymerase leading to transcription termination (Adhya et aL, 1976;Platt and Richardson, 1992;Platt, 1994). It has been proposed (Zheng and Friedman, 1994) that in the absence of NusA, as in the strain carrying AnusA533, RNA polymerase elongates more rapidly causing a general uncoupling of transcription and translation (Das and Wolska, 1984). This allows access by Rho to the paused polymerase, leading to premature transcription termination throughout the genome.…”

Section: Nusamentioning

confidence: 99%

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Transcription antitermination: the λ paradigm updated

Friedman

Court²

1995

Molecular Microbiology

128

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“…Antitermination by N requires a cis-acting RNA element, called the nut site, which consists of two functional components, boxA and boxB (Salstrom and Szybalski 1978;de Crombrugge et al 1979;Olson et al 1982;Das and Wolska 1984;Horwitz et al 1987). NusA, as well as the E. coli proteins NusB, NusE (ribosomal protein S10), NusG, RNA polymerase, and the nut site on the phage RNA, take part in multiple interactions within the N-modified transcription complex (for review, see Friedman 1988;Greenblatt et al 1993).…”

mentioning

confidence: 99%

The α subunit of E. coli RNA polymerase activates RNA binding by NusA

Mah¹,

Kuznedelov²,

Mushegian³

et al. 2000

Genes Dev.

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The Escherichia coli NusA protein modulates pausing, termination, and antitermination by associating with the transcribing RNA polymerase core enzyme. NusA can be covalently cross-linked to nascent RNA within a transcription complex, but does not bind RNA on its own. We have found that deletion of the 79 carboxy-terminal amino acids of the 495-amino-acid NusA protein allows NusA to bind RNA in gel mobility shift assays. The carboxy-terminal domain (CTD) of the ␣ subunit of RNA polymerase, as well as the bacteriophage N gene antiterminator protein, bind to carboxy-terminal regions of NusA and enable full-length NusA to bind RNA. Binding of NusA to RNA in the presence of ␣ or N involves an amino-terminal S1 homology region that is otherwise inactive in full-length NusA. The interaction of the ␣-CTD with full-length NusA stimulates termination. N may prevent termination by inducing NusA to interact with N utilization (nut) site RNA rather than RNA near the 3 end of the nascent transcript. Sequence analysis showed that the ␣-CTD contains a modified helix-hairpin-helix motif (HhH), which is also conserved in the carboxy-terminal regions of some eubacterial NusA proteins. These HhH motifs may mediate protein-protein interactions in NusA and the ␣-CTD.

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Transcription antitermination in vitro by lambda N gene product: Requirement for a phage nut site and the products of host nusA, nusB, and nusE genes

Cited by 81 publications

References 43 publications

Structure, sequence, and position of the stem-loop in tar determine transcriptional elongation by tat through the HIV-1 long terminal repeat.

Structure, sequence, and position of the stem-loop in tar determine transcriptional elongation by tat through the HIV-1 long terminal repeat.

Transcription antitermination: the λ paradigm updated

The α subunit of E. coli RNA polymerase activates RNA binding by NusA

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