Interprotomer Communication and Functional Asymmetry in H/ACA snoRNPs.

ABSTRACT: H/ACA small nucleolar ribonucleoproteins (H/ACA snoRNPs) facilitate essential cellular processes such as RNA modification, folding, and stability. Here, we present multiple cryo-EM structures of endogenous, catalytically active insect H/ACA snoRNPs containing two protomers assembled on a two-hairpin H/ACA snoRNA. By characterizing key protein-protein and protein-RNA interactions, we reveal the coordination of pseudouridylation activity across the two protomers which explains the predominance of two-hairpin structures in eukaryotic H/ACA snoRNAs. Moreover, we discovered that several mutations in H/ACA proteins associated with Dyskeratosis congenita directly impair pseudouridine formation suggesting how these mutations disrupt RNA modification and ribosome biogenesis in this disease. Additio

SUBMITTER: Panwar HS 

PROVIDER: S-EPMC12157440 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature