Sni445 recruits box C/D snoRNPs snR4 and snR45 to guide ribosomal RNA acetylation by Kre33.

ABSTRACT: Eukaryotic ribosome synthesis is a highly complex, multistep process that is best characterized in the yeast Saccharomyces cerevisiae. It is orchestrated by >200 ribosome assembly factors and 75 small nucleolar ribonucleoproteins (snoRNPs), which guide site-specific chemical modifications of precursor rRNA (pre-rRNA). While canonical box C/D snoRNPs guide 2'-O-methylation, the atypical box C/D snoRNPs snR4 and snR45 guide acetylation of 18S rRNA residues C1280 and C1773, respectively, catalyzed by the acetyltransferase Kre33. Here, we identify and characterize Ynl050c/Sni445 as a novel ribosome assembly factor and previously unrecognized auxiliary component of the snR4 and snR45 box C/D snoRNPs. Sni445 associates with snR4 and snR45 in their free form and is required for their stable incor

SUBMITTER: Hafner J 

PROVIDER: S-EPMC12848939 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature