CHARACTERIZATION OF THE PRO-INFLAMMATORY AND ANTIVIRAL ACTIVITY OF THE CELLULAR PROTEIN RBM10 IN RESPONSE TO DENGUE VIRUS INFECTION.

MAGALNIK, MELINA; POZZI, BERTA; SREBROW, ANABELLA

Congreso; LIX Reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular SAIB; 2023

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular SAIB

In the context of a mammalian cell infection by dengue virus, multiple mechanisms are activated as part of what is referred to as the innate cellular immune response. Among these mechanisms, activation of the cytoplasmic RNA receptor RIG-I triggers a signaling cascade that leads to the expression of pro-inflammatory cytokines and interferons. When secreted, these act in an autocrine or paracrine manner, leading to a strong induction of genes known as Interferon Stimulated Genes. One of these genes is the spermidine/spermine acetyltransferase "SAT1", whose pre-mRNA is regulated by alternative splicing, resulting in an antiviral coding mRNA isoform and a non-coding isoform that is degraded by Non-sense Mediated Decay. This splicing event is regulated by the RNA-binding protein and auxiliary factor RBM10. We recently reported that high levels of RBM10 dampen DENV replication, induce the expression of innate immune response genes, and increase the proportion of the antiviral isoform of SAT1 pre-mRNA. Furthermore, we found that RBM10 interacts with viral RNA and RIG-I and stimulates its non-degradative ubiquitination. In the same line, we observed an increase in the cytoplasmic localization of RBM10 in the context of infection, as well as upon treatment of cultured cells with interferon. When analyzing an RBM10 mutant that displays a more cytoplasmic localization, we found that while its splicing activity decreases in comparison to the wild-type protein, it does not lose its interaction with RIG-I nor its ability to regulate the ubiquitination of this protein. We propose that RBM10 exerts its antiviral action not only by regulating alternative splicing within the cellular nucleus, but also through its cytoplasmic interaction with RIG-I. In the context of dengue virus infection, we plan to analyze RBM10 interactome as well as a plethora of post-translational modifications that may regulate its subcellular localization, its interaction with RIG-I and viral RNA, its splicing factor activity, and its ability to induce the expression of immune response genes.