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The Reb1-homologue Ydr026c/Nsi1 is required for efficient RNA polymerase I termination in yeast.

ABSTRACT: Several DNA cis-elements and trans-acting factors were described to be involved in transcription termination and to release the elongating RNA polymerases from their templates. Different models for the molecular mechanism of transcription termination have been suggested for eukaryotic RNA polymerase I (Pol I) from results of in vitro and in vivo experiments. To analyse the molecular requirements for yeast RNA Pol I termination, an in vivo approach was used in which efficient termination resulted in growth inhibition. This led to the identification of a Myb-like protein, Ydr026c, as bona fide termination factor, now designated Nsi1 (NTS1 silencing protein 1), since it was very recently described as silencing factor of ribosomal DNA. Possible Nsi1 functions in regard to the mechanism of transcription termination are discussed.

SUBMITTER: Reiter A

PROVIDER: S-EPMC3419925 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Senataxin homologue Sen1 is required for efficient termination of RNA polymerase III transcription.

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Genome-wide mapping of yeast RNA polymerase II termination.

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cis- and trans-Acting determinants of transcription termination by yeast RNA polymerase II.

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Regulation of replication termination by Reb1 protein-mediated action at a distance.

Project description:DNA transactions driven by long-range protein-mediated inter- and intrachromosomal interactions have been reported to influence gene expression. Here, we report that site-specific replication termination in Schizosaccharomyces pombe is modulated by protein-mediated interactions between pairs of Ter sites located either on the same or on different chromosomes. The dimeric Reb1 protein catalyzes termination and mediates interaction between Ter sites. The Reb1-dependent interactions between two antiparallel Ter sites in cis caused looping out of the intervening DNA in vitro and enhancement of fork arrest in vivo. A Ter site on chromosome 2 interacted pairwise with two Ter sites located on chromosome 1 by chromosome kissing. Mutational inactivation of the major interacting Ter site on chromosome 1 significantly reduced fork arrest at the Ter site on chromosome 2, thereby revealing a cooperative mechanism of control of replication termination.

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RNA Polymerase II CTD Tyrosine 1 is Required for Efficient Termination by the Nrd1-Nab3-Sen1 Pathway

Project description:This SuperSeries is composed of the SubSeries listed below.

2019-01-21 | GSE115028 | GEO

Genome-wide mapping of yeast RNA polymerase II termination

Project description:Using a modification of the yeast anchor away and PAR-CLIP protocols, we have mapped the position of Pol II genome-wide in living yeast cells after depletion of components of either the polyadenylation (pA) or non-pA termination complexes. Depletion of Ysh1 from the nucleus does not lead to readthrough transcription. In contrast, depletion of the termination factor Nrd1 leads to widespread runaway elongation of non-pA transcripts. Depletion of Sen1 also leads to readthrough at non-pA terminators but in contrast to Nrd1 this readthrough appears less processive. Examination of PAR-CLIP sequencing data of Pol II after removal of different transcriptional termination factors.

2014-07-24 | E-GEOD-56435 | biostudies-arrayexpress

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Project description:In plants, transgenes with inverted repeats are used to induce efficient RNA silencing, which is also frequently induced by highly transcribed sense transgenes. RNA silencing induced by sense transgenes is dependent on RNA-dependent RNA polymerase 6 (RDR6), which converts single-stranded (ss) RNA into double-stranded (ds) RNA. By contrast, it has been proposed that RNA silencing induced by self-complementary hairpin RNA (hpRNA) does not require RDR6, because the hpRNA can directly fold back on itself to form dsRNA. However, it is unclear whether RDR6 plays a role in hpRNA-induced RNA silencing by amplifying dsRNA to spread RNA silencing within the plant. To address the efficiency of hpRNA-induced RNA silencing in the presence or absence of RDR6, Wild type (WT, Col-0) and rdr6-11 Arabidopsis thaliana lines expressing green fluorescent protein (GFP) were generated and transformed with a GFP-RNA interference (RNAi) construct. Whereas most GFP-RNAi-transformed WT lines exhibited almost complete silencing of GFP expression in the T1 generation, various levels of GFP expression remained among the GFP-RNAi-transformed rdr6-11 lines. Homozygous expression of GFP-RNAi in the T3 generation was not sufficient to induce complete GFP silencing in several rdr6-11 lines. Our results indicate that RDR6 is required for efficient hpRNA-induced RNA silencing in plants.

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