scholarly journals Identification of three sequence motifs in the transcription termination factor Sen1 that mediate direct interactions with Nrd1

2018 ◽  
Author(s):  
Yinglu Zhang ◽  
Yujin Chun ◽  
Stephen Buratowski ◽  
Liang Tong

AbstractThe Nrd1-Nab3-Sen1 (NNS) complex carries out the transcription termination of noncoding RNAs (ncRNAs) in yeast, although the detailed interactions among its subunits remain obscure. Here we have identified three sequence motifs in Sen1 that mediate direct interactions with the RNA polymerase II CTD interaction domain (CID) of Nrd1, determined the crystal structures of these Nrd1 interaction motifs (NIMs) bound to the CID, and characterized the interactions in vitro and in yeast.

2019 ◽  
Author(s):  
Melanie J. Fox ◽  
Jose F. Victorino ◽  
Whitney R. Smith-Kinnaman ◽  
Sarah A. Peck Justice ◽  
Hongyu Gao ◽  
...  

ABSTRACTRNA Polymerase II (RNAPII) transcription termination is regulated by the phosphorylation status of the C-terminal domain (CTD). Using disruption-compensation (DisCo) protein-protein interaction network analysis, interaction changes were observed within the termination machinery as a consequence of deletion of the serine 5 RNAPII CTD phosphatase Rtr1. Interactions between RNAPII and the cleavage factor IA (CF1A) subunit Pcf11 were reduced in rtr1Δ, whereas interactions with the CTD and RNA-binding termination factor Nrd1 were increased. These changes could be the result of altered interactions between the termination machinery and/or increased levels of premature termination of RNAPII. Transcriptome analysis in rtr1Δ cells found decreased pervasive transcription and a shift in balance of expression of sense and antisense transcripts. Globally, rtr1Δ leads to decreases in noncoding RNAs that are linked to the Nrd1, Nab3 and Sen1 (NNS)-dependent RNAPII termination pathway. Genome-wide analysis of RNAPII and Nrd1 occupancy suggests that loss of RTR1 leads to increased termination at noncoding genes and increased efficiency of snRNA termination. Additionally, premature termination increases globally at protein-coding genes where NNS is recruited during early elongation. The effects of rtr1Δ on RNA expression levels were erased following deletion of the exosome subunit Rrp6, which works with the NNS complex to rapidly degrade terminated noncoding RNAs. Overall, these data suggest that Rtr1 restricts the NNS-dependent termination pathway in WT cells to prevent premature RNAPII termination of mRNAs and ncRNAs. Additionally, Rtr1 phosphatase activity facilitates low-level elongation of noncoding transcripts that impact the transcriptome through RNAPII interference.AUTHOR SUMMARYMany cellular RNAs including those that encode for proteins are produced by the enzyme RNA Polymerase II. In this work, we have defined a new role for the phosphatase Rtr1 in the regulation of RNA Polymerase II progression from the start of transcription to the 3’ end of the gene where the nascent RNA from protein-coding genes is typically cleaved and polyadenylated. Deletion of the gene that encodes RTR1 leads to changes in the interactions between RNA polymerase II and the termination machinery. Rtr1 loss also causes early termination of RNA Polymerase II at many of its target gene types including protein coding genes and noncoding RNAs. Evidence suggests that the premature termination observed in RTR1 knockout cells occurs through the termination factor and RNA binding protein Nrd1 and its binding partner Nab3. Additionally, many of the prematurely terminated noncoding RNA transcripts are degraded by the Rrp6-containing nuclear exosome, a known component of the Nrd1-Nab3 termination coupled RNA degradation pathway. These findings suggest that Rtr1 normally promotes elongation of RNA Polymerase II transcripts through preventation of Nrd1-directed termination.


PLoS Genetics ◽  
2020 ◽  
Vol 16 (3) ◽  
pp. e1008317 ◽  
Author(s):  
Jose F. Victorino ◽  
Melanie J. Fox ◽  
Whitney R. Smith-Kinnaman ◽  
Sarah A. Peck Justice ◽  
Katlyn H. Burriss ◽  
...  

1998 ◽  
Vol 42 (3) ◽  
pp. 571-578 ◽  
Author(s):  
Lucia Carrano ◽  
Cecilia Bucci ◽  
Roberto De Pascalis ◽  
Alfredo Lavitola ◽  
Filomena Manna ◽  
...  

ABSTRACT Bicyclomycin is a commercially important antibiotic that has been shown to be effective against many gram-negative bacteria. Genetic and biochemical evidence indicates that the antibiotic interferes with RNA metabolism in Escherichia coli by inhibiting the activity of transcription termination factor Rho. However, the precise mechanism of inhibition is not completely known. In this study we have used in vitro transcription assays to analyze the effects of bicyclomycin on the termination step of transcription. The Rho-dependent transcription termination region located within thehisG cistron of Salmonella typhimurium has been used as an experimental system. The possible interference of the antibiotic with the various functions of factor Rho, such as RNA binding at the primary site, ATP binding, and hexamer formation, has been investigated by RNA gel mobility shift, photochemical cross-linking, and gel filtration experiments. The results of these studies demonstrate that bicyclomycin does not interfere with the binding of Rho to the loading site on nascent RNA. Binding of the factor to ATP is not impeded, on the contrary, the antibiotic appears to decrease the apparent equilibrium dissociation constant for ATP in photochemical cross-linking experiments. The available evidence suggests that this decrease might be due to an interference with the correct positioning of ATP within the nucleotide-binding pocket leading b an inherent block of ATP hydrolysis. Possibly, as a consequence of this interference, the antibiotic also prevents ATP-dependent stabilization of Rho hexamers.


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