The methyltransferase domain of the Respiratory Syncytial Virus L protein catalyzes cap N7 and 2’-O-methylation

• DOI: 10.1371/journal.ppat.1009562
• Publication Date: 2021-05-06T18:40:46Z
• Authors: Priscila Sutto-Ortiz; Sergey Tcherniuk; Nina Ysebaert; Pravien Abeywickrema; Mathieu Noël; Alice Decombe; Françoise Debart; Jean-Jacques Vasseur; Bruno Canard; Dirk Roymans; Peter Rigaux; Jean-François Elé...; Etienne Decroly
• Keywords: Protein methylation

Respiratory syncytial virus (RSV) is a negative sense single-stranded RNA and one of the main causes severe lower respiratory tract infections in infants young children. RSV replication/transcription capping are ensured by viral Large (L) protein. The L protein contains polymerase domain associated with polyribonucleotidyl transferase its N-terminus, methyltransferase (MTase) followed C-terminal (CTD) enriched basic amino acids at C-terminus. MTase-CTD Mononegavirales forms clamp to accommodate that subsequently methylated on cap structure depending virus, internal positions. These enzymatic activities essential for efficient mRNA translation into proteins, prevent recognition uncapped innate immunity sensors. In this work, we demonstrated RSV, as well full-length complex phosphoprotein (P), catalyzes N7- 2'-O-methylation short sequence corresponds 5' end mRNA. Using different experimental systems, showed methylates preference N7-methylation first reaction. However, did not observe cap-independent methylation, recently evidenced Ebola MTase. We also found μM concentrations, sinefungin, S-adenosylmethionine analogue, inhibits MTase activity domain. Altogether, these results suggest specifically recognizes decorated which required immune system subversion.