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Title | Structural insights into RNA polymerase III-mediated transcription termination through trapping poly-deoxythymidine. |
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Journal, issue, pages | Nat Commun, Vol. 12, Issue 1, Page 6135, Year 2021 |
Publish date | Oct 21, 2021 |
Authors | Haifeng Hou / Yan Li / Mo Wang / Aijun Liu / Zishuo Yu / Ke Chen / Dan Zhao / Yanhui Xu / |
PubMed Abstract | Termination of the RNA polymerase III (Pol III)-mediated transcription requires the conversion of an elongation complex (EC) to a pre-termination complex (PTC) on poly-deoxythymidine (dT)-containing ...Termination of the RNA polymerase III (Pol III)-mediated transcription requires the conversion of an elongation complex (EC) to a pre-termination complex (PTC) on poly-deoxythymidine (dT)-containing non-template strand, a mechanism distinct from Pol I and Pol II. Here, our in vitro transcription elongation assay showed that 5-7 dT-containing DNA template led to transcription termination of Pol III, but not Pol I or Pol II. We assembled human Pol III PTC on a 7 dT-containing DNA template and determined the structure at 3.6 Å resolution. The structure reveals that poly-dT are trapped in a narrow exit tunnel formed by RPC2. A hydrophobic gate of the exit tunnel separates the bases of two connected deoxythymidines and may prevent translocation of the non-template strand. The fork loop 2 stabilizes both template and non-template strands around the transcription fork, and may further prevent strand translocation. Our study shows that the Pol III-specific exit tunnel and FL2 allow for efficient translocation of non-poly-dT sequence during transcription elongation but trap poly-dT to promote DNA retention of Pol III, revealing molecular mechanism of poly-dT-dependent transcription termination of Pol III. |
External links | Nat Commun / PubMed:34675218 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.6 Å |
Structure data | EMDB-31621, PDB-7fji: EMDB-31622, PDB-7fjj: |
Chemicals | ChemComp-ZN: ChemComp-SF4: ChemComp-MG: |
Source |
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Keywords | TRANSCRIPTION/RNA/DNA / RNA Polymerase III / elongation / pre-termination / TRANSCRIPTION / TRANSCRIPTION-RNA-DNA complex |