Biology subjects

Bonazza, S.

Publications and source records attributed to Bonazza, S..

3 recordsLinked to original sources

bioRxiv2024

Myoferlin is an essential component of late-stage vRNP trafficking vesicles for enveloped RNA viruses.

The Rab11a endosomal recycling pathway is exploited by important respiratory RNA viruses such as IAV and RSV, aiding viral egress from the apical surface of polarized epithelial cells. Late in infection, Rab11a-containing vesicles specifically transport viral ribonucleoprotein (vRNP) complexes towards the cell surface before packaging and budding. Rather than employing traditional Rab11a-positive recycling endosomes, virus-infected cells generate remodelled Rab11a-containing vesicles, as observed during IAV infection. Besides Rab11a, no other conserved host co-factors have been identified among these various vRNP trafficking vesicles. Here we discovered and confirmed myoferlins association with IAV vRNPs in the cytoplasm and colocalisation with Rab11a during late stages of infection. We also found that this role was conserved in late-stage vRNP trafficking of other viruses, including RSV and SeV. Myoferlin likely recruits the EHD family of proteins, which are involved in endosomal biogenesis, to these unique vRNP trafficking endosomes, highlighting myoferlins pivotal role in viral replication.

microbiology↗

bioRxiv2023

Identifying cellular RNA-binding proteins during infection uncovers a role for MKRN2 in influenza mRNA trafficking

Utilisation of RNA-binding proteins (RBPs) is an important aspect of post-transcriptional regulation of viral RNA. Viruses such as influenza A viruses (IAV) interact with RBPs to regulate processes including splicing, nuclear export and trafficking, while also encoding RBPs within their genomes, such as NP and NS1. But with almost 1000 RBPs encoded within the human genome it is still unclear what role, if any, many of these proteins play during viral replication. Using the RNA interactome capture (RIC) technique, we isolated RBPs from IAV infected cells to unravel the RBPome of mRNAs from IAV infected human cells. This led to the identification of one particular RBP, MKRN2, that associates with and positively regulates IAV mRNA. Through further validation, we determined that MKRN2 is involved in the nuclear-cytoplasmic trafficking of IAV mRNA likely through an association with the RNA export mediator GLE1. In the absence of MKRN2, IAV mRNAs accumulate in the nucleus of infected cells, which we suspect leads to their degradation by the nuclear RNA exosome complex. MKRN2, therefore, appears to be required for the efficient nuclear export of IAV mRNAs in human cells.

microbiology↗

bioRxiv2023

The RBPome of influenza A virus mRNA reveals a role for TDP-43 in viral replication

Recent technical advances have significantly improved our understanding of the RNA-binding protein (RBP) repertoire present within eukaryotic cells, with a particular focus on the RBPs that interact with cellular polyadenylated mRNAs. However, recent studies utilising the same technologies have begun to tease apart the RBP interactome of viral mRNAs, notably SARS-CoV-2, revealing both similarities and differences between the RBP profiles of viral and cellular mRNAs. Herein, we comprehensively identified the RBPs that associate with the NP mRNA of an influenza A virus. Moreover, we provide evidence that the viral polymerase is essential for the recruitment of RPBs to viral mRNAs through direct polymerase-RBP interactions during transcription. We show that loss of TDP-43, which associates with the viral mRNAs, results in lower levels of viral mRNAs within infected cells, and a decreased yield of infectious viral particles. Overall, our results uncover an important role for TDP-43 in the influenza A virus replication cycle via a direct interaction with viral mRNAs, and point to a role of the viral polymerase in orchestrating the assembly of viral mRNPs.

microbiology↗