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  • 1
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2006-07-29
    Description: Fidelity of template-dependent nucleic acid synthesis is the main determinant of stable heredity and error-free gene expression. The mechanism (or mechanisms) ensuring fidelity of transcription by DNA-dependent RNA polymerases (RNAPs) is not fully understood. Here, we show that the 3' end-proximal nucleotide of the nascent transcript stimulates hydrolysis of the penultimate phosphodiester bond by providing active groups and coordination bonds to the RNAP active center. This stimulation is much higher in the case of misincorporated nucleotide. We show that during transcription elongation, the hydrolytic reaction stimulated by misincorporated nucleotides proofreads most of the misincorporation events and thus serves as an intrinsic mechanism of transcription fidelity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zenkin, Nikolay -- Yuzenkova, Yulia -- Severinov, Konstantin -- New York, N.Y. -- Science. 2006 Jul 28;313(5786):518-20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA. nicserzen@mail.ru〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16873663" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Monophosphate/metabolism ; Base Pairing ; Binding Sites ; Catalysis ; Cytidine Monophosphate/metabolism ; DNA/metabolism ; DNA-Directed RNA Polymerases/*metabolism ; Hydrogen Bonding ; Hydrolysis ; Kinetics ; Magnesium/metabolism ; Models, Genetic ; Nucleotides/metabolism ; RNA, Messenger/*metabolism ; Templates, Genetic ; Thermus/enzymology ; *Transcription, Genetic
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2013-07-03
    Description: Gene expression in organisms involves many factors and is tightly controlled. Although much is known about the initial phase of transcription by RNA polymerase III (Pol III), the enzyme that synthesizes the majority of RNA molecules in eukaryotic cells, termination is poorly understood. Here, we show that the extensive structure of Pol III-synthesized transcripts dictates the release of elongation complexes at the end of genes. The poly-T termination signal, which does not cause termination in itself, causes catalytic inactivation and backtracking of Pol III, thus committing the enzyme to termination and transporting it to the nearest RNA secondary structure, which facilitates Pol III release. Similarity between termination mechanisms of Pol III and bacterial RNA polymerase suggests that hairpin-dependent termination may date back to the common ancestor of multisubunit RNA polymerases.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3760304/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3760304/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nielsen, Soren -- Yuzenkova, Yulia -- Zenkin, Nikolay -- 202994/European Research Council/International -- BB/F013558/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- BB/J006378/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- Biotechnology and Biological Sciences Research Council/United Kingdom -- New York, N.Y. -- Science. 2013 Jun 28;340(6140):1577-80. doi: 10.1126/science.1237934.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Baddiley-Clark Building, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23812715" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Molecular Sequence Data ; Nucleic Acid Conformation ; Poly T/metabolism ; Poly U/metabolism ; RNA Polymerase III/*metabolism ; RNA, Ribosomal, 5S/chemistry/genetics ; RNA, Transfer, Tyr/chemistry/genetics ; Saccharomyces cerevisiae/*enzymology/genetics ; *Transcription Termination, Genetic
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2010-06-01
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 4
    Publication Date: 2015-02-18
    Description: Collisions between paused transcription elongation complexes and replication forks inevitably happen, which may lead to collapse of replication fork and could be detrimental to cells. Bacterial transcription factor DksA and its cofactor alarmone ppGpp were proposed to contribute to prevention of such collisions, although the mechanism of this activity remains elusive. Here we show that DksA/ppGpp do not destabilise transcription elongation complexes or inhibit their backtracking, as was proposed earlier. Instead, we show, both in vitro and in vivo , that DksA/ppGpp increase fidelity of transcription elongation by slowing down misincorporation events. As misincorporation events cause temporary pauses, contribution to fidelity suggests the mechanism by which DksA/ppGpp contribute to prevention of collisions of transcription elongation complexes with replication forks. DksA is only the second known accessory factor, after transcription factor Gre, that increases fidelity of RNA synthesis in bacteria.
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
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  • 5
    Publication Date: 2014-09-27
    Description: Transcription by RNA polymerase may be interrupted by pauses caused by backtracking or misincorporation that can be resolved by the conserved bacterial Gre-factors. However, the consequences of such pausing in the living cell remain obscure. Here, we developed molecular biology and transcriptome sequencing tools in the human pathogen Streptococcus pneumoniae and provide evidence that transcription elongation is rate-limiting on highly expressed genes. Our results suggest that transcription elongation may be a highly regulated step of gene expression in S. pneumoniae . Regulation is accomplished via long-living elongation pauses and their resolution by elongation factor GreA. Interestingly, mathematical modeling indicates that long-living pauses cause queuing of RNA polymerases, which results in ‘transcription traffic jams’ on the gene and thus blocks its expression. Together, our results suggest that long-living pauses and RNA polymerase queues caused by them are a major problem on highly expressed genes and are detrimental for cell viability. The major and possibly sole function of GreA in S. pneumoniae is to prevent formation of backtracked elongation complexes.
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
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  • 6
    Publication Date: 2016-04-08
    Description: Coupled transcription and translation in bacteria are tightly regulated. Some small RNAs (sRNAs) control aspects of this coupling by modifying ribosome access or inducing degradation of the message. Here, we show that sRNA IsrA (IS61 or McaS) specifically associates with core enzyme of RNAP in vivo and in vitro , independently of factor and away from the main nucleic-acids-binding channel of RNAP. We also show that, in the cells, IsrA exists as ribonucleoprotein particles (sRNPs), which involve a defined set of proteins including Hfq, S1, CsrA, ProQ and PNPase. Our findings suggest that IsrA might be directly involved in transcription or can participate in regulation of gene expression by delivering proteins associated with it to target mRNAs through its interactions with transcribing RNAP and through regions of sequence-complementarity with the target. In this eukaryotic-like model only in the context of a complex with its target, IsrA and its associated proteins become active. In this manner, in the form of sRNPs, bacterial sRNAs could regulate a number of targets with various outcomes, depending on the set of associated proteins.
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
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  • 7
    Publication Date: 2013-11-02
    Description: Transcription elongation consists of repetition of the nucleotide addition cycle: phosphodiester bond formation, translocation and binding of the next nucleotide. Inhibitor of multi-subunit RNA polymerase tagetitoxin (TGT) enigmatically slows down addition of nucleotides in a sequence-dependent manner, only at certain positions of the template. Here, we show that TGT neither affects chemistry of RNA synthesis nor induces backward translocation, nor competes with the nucleoside triphosphate (NTP) in the active center. Instead, TGT increases the stability of the pre-translocated state of elongation complex, thus slowing down addition of the following nucleotide. We show that the extent of inhibition directly depends on the intrinsic stability of the pre-translocated state. The dependence of translocation equilibrium on the transcribed sequence results in a wide distribution (~1–10 3 -fold) of inhibitory effects of TGT at different positions of the template, thus explaining sequence-specificity of TGT action. We provide biochemical evidence that, in pre-translocated state, TGT stabilizes folded conformation of the Trigger Loop, which inhibits forward and backward translocation of the complex. The results suggest that Trigger Loop folding in the pre-translocated state may serve to reduce backtracking of the elongation complex. Overall, we propose that translocation may be a limiting and highly regulated step of RNA synthesis.
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
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  • 8
    Publication Date: 2015-07-25
    Description: Regulation of transcription elongation is based on response of RNA polymerase (RNAP) to various pause signals and is modulated by various accessory factors. Here we report that a 7 kDa protein p7 encoded by bacteriophage Xp10 acts as an elongation processivity factor of RNAP of host bacterium Xanthomonas oryzae , a major rice pathogen. Our data suggest that p7 stabilizes the upstream DNA duplex of the elongation complex thus disfavouring backtracking and promoting forward translocated states of the elongation complex. The p7-induced ‘pushing’ of RNAP and modification of RNAP contacts with the upstream edge of the transcription bubble lead to read-through of various types of pauses and termination signals and generally increase transcription processivity and elongation rate, contributing for transcription of an extremely long late genes operon of Xp10. Forward translocation was observed earlier upon the binding of unrelated bacterial elongation factor NusG, suggesting that this may be a general pathway of regulation of transcription elongation.
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    Electronic ISSN: 1362-4962
    Topics: Biology
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  • 9
    Publication Date: 2013-08-09
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
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  • 10
    Publication Date: 2011-01-25
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
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