GPATCH4 regulates rRNA and snRNA 2’-O-methylation in both DHX15-dependent and DHX15-independent mannersGPATCH4 regulates rRNA and snRNA 2’-O-methylation in both DHX15-dependent and DHX15-independent manners

ABSTRACT: Regulation of RNA helicase activity, often accomplished by protein cofactors, is essential to ensure target specify within the complex cellular environment. The largest family of RNA helicase cofactors are the G-patch proteins, but the cognate RNA helicases and cellular functions of numerous human G-patch proteins remain elusive. Here, we discover that GPATCH4 is a stimulatory cofactor of DHX15 that interacts with the helicase in the nucleolus via residues in its G-patch domain. We reveal that GPATCH4 associates with pre-ribosomal particles, and crosslinks to the transcribed ribosomal DNA locus and precursor ribosomal RNAs as well as binding to small nucleolar- and small Cajal body-associated- RNAs that guide rRNA and snRNA modifications. Global analysis of rRNA and snRNA 2’-O-methylation revealed that lack of GPATCH4 impairs methylation at various sites. We further demonstrated that the regulation of 2’-O-methylation by GPATCH4 is both dependent on, and independent of, its interaction with DHX15. Intriguingly, the ATPase activity of DHX15 is necessary for efficient methylation of DHX15-dependent sites, suggesting a function of DHX15 in regulating snoRNA-guided 2’-O-methylation of rRNA that requires activation by GPATCH4. Overall, our findings extend knowledge on RNA helicase regulation by G-patch proteins and also provide important new insights into the mechanisms regulating installation of rRNA and snRNA modifications, which are essential for ribosome function and pre-mRNA splicing.

INSTRUMENT(S):

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Aleksandar Chernev  

LAB HEAD: Henning Urlaub

PROVIDER: PXD043301 | Pride | 2025-08-15

REPOSITORIES: Pride