Authors: Myeonghwan Kim, Youngjoon Pyo, Seong-In Hyun, Minseok Jeong, Yeon Choi, V. Narry Kim
Published: 2025-04-04
Source: Full article
Exogenous messenger RNAs (mRNAs) require cellular machinery for delivery and translation but also encounter inhibitory factors. To investigate their regulation, we performed genome-wide CRISPR screens with in vitro–transcribed mRNAs in lipid nanoparticles (LNPs). Heparan sulfate proteoglycans (HSPGs) and vacuolar adenosine triphosphatase (V-ATPase) were identified as mediators of LNP uptake and endosomal escape, respectively. TRIM25—an RNA binding E3 ubiquitin ligase—emerged as a key suppressor inducing turnover of both linear and circular mRNAs. The endoribonucleases N4BP1 and KHNYN, along with the antiviral protein ZAP, act redundantly in TRIM25-dependent surveillance. TRIM25 specifically targets mRNAs delivered by endosomes, and its RNA affinity increases at acidic pH, suggesting activation by protons released from ruptured endosomes.