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In vitro structural maturation of an early stage pre-40S particle coupled with U3 snoRNA release and central pseudoknot formation.

ABSTRACT: The transition of the 90S to the pre-40S pre-ribosome is a decisive step in eukaryotic small subunit biogenesis leading to a first pre-40S intermediate (state Dis-C or primordial pre-40S), where the U3 snoRNA keeps the nascent 18S rRNA locally immature. We in vitro reconstitute the ATP-dependent U3 release from this particle, catalyzed by the helicase Dhr1, and follow this process by cryo-EM revealing two successive pre-40S intermediates, Dis-D and Dis-E. The latter has lost not only U3 but all residual 90S factors including the GTPase Bms1. In vitro remodeling likewise induced the formation of the central pseudoknot, a universally conserved tertiary RNA structure that comprises the core of the small subunit decoding center. Thus, we could structurally reveal a key tertiary RNA folding step that is essential to form the active 40S subunit.

SUBMITTER: Cheng J

PROVIDER: S-EPMC9723636 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature

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In vitro structural maturation of an early stage pre-40S particle coupled with U3 snoRNA release and central pseudoknot formation.

Cheng Jingdong J La Venuta Giuseppe G Lau Benjamin B Berninghausen Otto O Beckmann Roland R Hurt Ed E

Nucleic acids research 20221101 20

The transition of the 90S to the pre-40S pre-ribosome is a decisive step in eukaryotic small subunit biogenesis leading to a first pre-40S intermediate (state Dis-C or primordial pre-40S), where the U3 snoRNA keeps the nascent 18S rRNA locally immature. We in vitro reconstitute the ATP-dependent U3 release from this particle, catalyzed by the helicase Dhr1, and follow this process by cryo-EM revealing two successive pre-40S intermediates, Dis-D and Dis-E. The latter has lost not only U3 but all ...[more]

PMID: 36263816

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