N6-methyladenosine reader protein YTHDC1 regulates influenza A virus NS segment splicing and replication

Abstract

N6-methyladenosine (m6A) modification on viral RNAs has a profound impact on infectivity. m6A is also a highly pervasive modification for influenza viral RNAs. However, its role in virus mRNA splicing is largely unknown. Here, we identify the m6A reader protein YTHDC1 as a host factor that associates with influenza A virus NS1 protein and modulates viral mRNA splicing. YTHDC1 levels are enhanced by IAV infection. We demonstrate that YTHDC1 inhibits NS splicing by binding to an NS 3′ splicing site and promotes IAV replication and pathogenicity in vitro and in vivo. Our results provide a mechanistic understanding of IAV-host interactions, a potential therapeutic target for blocking influenza virus infection, and a new avenue for the development of attenuated vaccines.

m6A Methylation in Regulation of Antiviral Innate Immunity

“…Knockdown of YTHDC1 enhanced NS segment splicing, while restoring YTHDC1 reversed this effect. The study concluded that the interaction between NS1 and YTHDC1 plays a critical role in regulating NS mRNA splicing during IAV infection [ 11 ].…”

“…The m 6 A modification plays a role in almost all biochemical processes related to RNA metabolism, influencing RNA stability [9] and regulating nuclear export of mRNA [10], splicing [11], and translation [12].…”

“…The reversibility of m 6 A methylation is controlled by writers and erasers, while reader proteins recognize the modified adenosines and regulate the associated biological functions (Figure 2). The m 6 A modification plays a role in almost all biochemical processes related to RNA metabolism, influencing RNA stability [9] and regulating nuclear export of mRNA [10], splicing [11], and translation [12].…”

GGCX promotes Eurasian avian-like H1N1 swine influenza virus adaption to interspecies receptor binding

“…The IAVs used in this study were A/Swine/HuBei/221/2016 (HuB/H1N1), A/Puerto Rico/8/1934 (PR8/H1N1), A/chicken/Shanghai/SC197/2013 (SH13/H9N2), and A/Hunan/42443/2015 (HN/H1N1). Recombinant viruses were generated in the genetic background of A/Hunan/42443/2015 (HN/H1N1) using an eight-plasmid reverse genetic system as described previously 42 . All other viruses were amplified using 10-day-old embryonic chicken eggs and titrated by determining TCID 50 values on MDCK cells.…”

RNA N6-methyladenosine methylation in influenza A virus infection

“…YTHDC1 directly targets and binds to the 3′ splicing site of NS mRNA, inhibiting the splicing of the NS segment dependent on the NS1 protein. Consequently, the expression of nuclear export protein (NEP) decreases, ultimately promoting the replication and pathogenicity of IAV, both in vitro and in vivo (Zhu Y. et al, 2023 ). In addition to the m 6 A modification, other modifications, such as 5-methylcytidine (m 5 C), N4-acetylcytidine (ac 4 C), and 2′ O -methylated nucleoside (N m ), can influence various steps in the viral replication cycle.…”