A pseudohelicase-centered complex couples assembly-dependent RNA cleavage to poly(UG)ylation
- 1University of Vienna
Abstract
Robust RNA interference in Caenorhabditis elegans requires Argonaute targeted RNAs to be cleaved by RDE 8 and poly(UG)ylated by MUT 2, generating templates for RNA dependent RNA polymerases that synthesize secondary small RNAs. RDE 8 and MUT 2 are physically coupled within the cleavage and poly(UG)ylation (CPUG) complex, together with the pseudonuclease NYN 1 and MUT 15, but how their activities are controlled and coordinated is unknown. Structural and biochemical analyses reveal that the RDE 8/NYN 1 nuclease module is autoinhibited, restricting cleavage outside CPUG. We identify MUT 15, the CPUG scaffold linking this nuclease module to MUT 2, as a pseudohelicase. MUT 15 remodels the nuclease module, licensing RDE 8 activity upon complex assembly. Reconstituted CPUG synthesizes long poly(UG) tails, with the substrate 3' end determining tailing efficiency and register. Within CPUG, RNA engagement by MUT 2 limits RDE 8 access, while poly(UG) tails themselves are not cleaved by RDE 8, preventing re cleavage. Together, CPUG couples assembly dependent RNA cleavage to downstream processing, imposing safety and directionality.
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BibTeX
@misc{busetto2026pseudohelicasecentered,
title = {{A pseudohelicase-centered complex couples assembly-dependent RNA cleavage to poly(UG)ylation}},
author = {V. Busetto and M. Brehm and A. Sgromo and M. Mager and L. Pshanichnaya and E. C. A. Becker and R. F. Ketting and S. L. Ameres and S. Falk},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.04.749402},
url = {https://www.biorxiv.org/content/10.64898/2026.09.04.749402v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - A pseudohelicase-centered complex couples assembly-dependent RNA cleavage to poly(UG)ylation
AU - V. Busetto
AU - M. Brehm
AU - A. Sgromo
AU - M. Mager
AU - L. Pshanichnaya
AU - E. C. A. Becker
AU - R. F. Ketting
AU - S. L. Ameres
AU - S. Falk
PY - 2026
DA - 2026/09/04
PB - bioRxiv
DO - 10.64898/2026.09.04.749402
UR - https://www.biorxiv.org/content/10.64898/2026.09.04.749402v1
AB - Robust RNA interference in Caenorhabditis elegans requires Argonaute targeted RNAs to be cleaved by RDE 8 and poly(UG)ylated by MUT 2, generating templates for RNA dependent RNA polymerases that synthesize secondary small RNAs. RDE 8 and MUT 2 are physically coupled within the cleavage and poly(UG)ylation (CPUG) complex, together with the pseudonuclease NYN 1 and MUT 15, but how their activities are controlled and coordinated is unknown. Structural and biochemical analyses reveal that the RDE 8/NYN 1 nuclease module is autoinhibited, restricting cleavage outside CPUG. We identify MUT 15, the CPUG scaffold linking this nuclease module to MUT 2, as a pseudohelicase. MUT 15 remodels the nuclease module, licensing RDE 8 activity upon complex assembly. Reconstituted CPUG synthesizes long poly(UG) tails, with the substrate 3' end determining tailing efficiency and register. Within CPUG, RNA engagement by MUT 2 limits RDE 8 access, while poly(UG) tails themselves are not cleaved by RDE 8, preventing re cleavage. Together, CPUG couples assembly dependent RNA cleavage to downstream processing, imposing safety and directionality.
ER -