Unraveling the mechanistic features of RNA polymerase II termination by the 5'-3' exoribonuclease Rat1.
Within a complex with Rai1, the 5'-3' exoribonuclease Rat1 promotes termination of RNA polymerase II (RNAPII) on protein-coding genes, but its underlying molecular mechanism is still poorly understood. Using in vitro transcription termination assays, we have found that RNAPII is prone to more effective termination by Rat1/Rai1 when its catalytic ... site is disrupted due to NTP misincorporation, implying that paused RNAPII, which is often found in vivo near termination sites, could adopt a similar configuration to Rat1/Rai1 and trigger termination. Intriguingly, yeast Rat1/Rai1 does not terminate Escherichia coli RNAP, implying that a specific interaction between Rat1/Rai1 and RNAPII may be required for termination. Furthermore, the efficiency of termination increases as the RNA transcript undergoing degradation by Rat1 gets longer, which suggests that Rat1 may generate a driving force for dissociating RNAPII from the template while degrading the nascent transcripts to catch up to the polymerase. These results indicate that multiple mechanistic features contribute to Rat1-mediated termination of RNAPII.
Mesh Terms:
Adenosine Triphosphate, Base Sequence, Exoribonucleases, Models, Genetic, Molecular Sequence Data, Mutation, Nuclear Proteins, RNA Polymerase II, RNA, Fungal, Saccharomyces cerevisiae Proteins, Transcription Factors, Transcription Termination, Genetic
Adenosine Triphosphate, Base Sequence, Exoribonucleases, Models, Genetic, Molecular Sequence Data, Mutation, Nuclear Proteins, RNA Polymerase II, RNA, Fungal, Saccharomyces cerevisiae Proteins, Transcription Factors, Transcription Termination, Genetic
Nucleic Acids Res.
Date: Mar. 11, 2015
PubMed ID: 25722373
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