RNA helicase Drs1 gates 25S rRNA domain III incorporation during early nucleolar pre-60S maturation

Abstract

Assembly of eukaryotic large ribosomal subunits (LSU) requires coordinated structural and compositional transitions within pre-60S particles, yet the underlying mechanisms remain poorly understood. Here, we show that the DEAD-box helicase Drs1 promotes early maturation across distinct regions of the pre-60S particle. Loss of Drs1 function causes accumulation of co-transcriptional intermediates retaining SSU processome components, indicating that Drs1 promotes timely separation of nascent LSU precursors from the small-subunit assembly pathway. Cryo-EM analyses reveal both a redistribution toward early nucleolar maturation states upon loss of Drs1, including Nsa1-deficient intermediates, and a confinement of Drs1-associated particles to states preceding stable incorporation of 25S rRNA domain III. Drs1 directly engages Erb1 through its unstructured N-terminal extension, promoting stable assembly of the Nop7-Erb1-Ytm1 module associated with domain III maturation. CRAC analysis localizes Drs1 to spatially clustered sites spanning the 5.8S and 25S rRNAs, encompassing domains I-IV. Together, these findings support a model in which Drs1 couples stabilization of assembly-factors with pre-rRNA remodeling across the pre-60S particle, thereby driving ordered early LSU maturation and the timed integration of domain III.

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BibTeX RIS

BibTeX

@misc{thoms2026helicase,
  title = {{RNA helicase Drs1 gates 25S rRNA domain III incorporation during early nucleolar pre-60S maturation}},
  author = {M. Thoms and S. Ayaz-Kök and K. Abe and H. Hamze and A. S. Thielen and T. Denk and B. Albert and N. Mikulic Vernik and L. Chitoiu and E. Laurent and E. Hurt and A. K. Henras and R. Beckmann and V. Mitterer},
  howpublished = {bioRxiv},
  year = {2026},
  month = sep,
  doi = {10.64898/2026.09.05.749353},
  url = {https://www.biorxiv.org/content/10.64898/2026.09.05.749353v1},
  note = {CC BY-NC-ND},
}

RIS

TY  - UNPB
TI  - RNA helicase Drs1 gates 25S rRNA domain III incorporation during early nucleolar pre-60S maturation
AU  - M. Thoms
AU  - S. Ayaz-Kök
AU  - K. Abe
AU  - H. Hamze
AU  - A. S. Thielen
AU  - T. Denk
AU  - B. Albert
AU  - N. Mikulic Vernik
AU  - L. Chitoiu
AU  - E. Laurent
AU  - E. Hurt
AU  - A. K. Henras
AU  - R. Beckmann
AU  - V. Mitterer
PY  - 2026
DA  - 2026/09/05
PB  - bioRxiv
DO  - 10.64898/2026.09.05.749353
UR  - https://www.biorxiv.org/content/10.64898/2026.09.05.749353v1
AB  - Assembly of eukaryotic large ribosomal subunits (LSU) requires coordinated structural and compositional transitions within pre-60S particles, yet the underlying mechanisms remain poorly understood. Here, we show that the DEAD-box helicase Drs1 promotes early maturation across distinct regions of the pre-60S particle. Loss of Drs1 function causes accumulation of co-transcriptional intermediates retaining SSU processome components, indicating that Drs1 promotes timely separation of nascent LSU precursors from the small-subunit assembly pathway. Cryo-EM analyses reveal both a redistribution toward early nucleolar maturation states upon loss of Drs1, including Nsa1-deficient intermediates, and a confinement of Drs1-associated particles to states preceding stable incorporation of 25S rRNA domain III. Drs1 directly engages Erb1 through its unstructured N-terminal extension, promoting stable assembly of the Nop7-Erb1-Ytm1 module associated with domain III maturation. CRAC analysis localizes Drs1 to spatially clustered sites spanning the 5.8S and 25S rRNAs, encompassing domains I-IV. Together, these findings support a model in which Drs1 couples stabilization of assembly-factors with pre-rRNA remodeling across the pre-60S particle, thereby driving ordered early LSU maturation and the timed integration of domain III.
ER  -

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