Host RNA Binding Proteins Research Articles

Translation elongation factor 1A is a component of the tombusvirus replicase complex and affects the stability of the p33 replication co-factor

Host RNA-binding proteins are likely to play multiple, integral roles during replication of plus-strand RNA viruses. To identify host proteins that bind to viral RNAs, we took a global approach based on the yeast proteome microarray, which contains 4080 purified yeast proteins. The biotin-labeled RNA probes included two distantly related RNA viruses, namely Tomato bushy stunt virus (TBSV) and Brome mosaic virus (BMV). Altogether, we have identified 57 yeast proteins that bound to TBSV RNA and/or BMV RNA. Among the identified host proteins, eleven bound to TBSV RNA and seven bound to BMV RNA with high selectivity, whereas the remaining 39 host proteins bound to both viral RNAs. The interaction between the TBSV replicon RNA and five of the identified host proteins was confirmed via gel-mobility shift and co-purification experiments from yeast. Over-expression of the host proteins in yeast, a model host for TBSV, revealed 4 host proteins that enhanced TBSV replication as well as 14 proteins that inhibited replication. Detailed analysis of one of the identified yeast proteins binding to TBSV RNA, namely translation elongation factor eEF1A, revealed that it is present in the highly purified tombusvirus replicase complex. We also demonstrate binding of eEF1A to the p33 replication protein and a known cis-acting element at the 3′ end of TBSV RNA. Using a functional mutant of eEF1A, we provide evidence on the involvement of eEF1A in TBSV replication.

Hfq Is a Regulator of F-Plasmid TraJ and TraM Synthesis inEscherichia coli

The F plasmid of Escherichia coli allows horizontal DNA transfer between an F(+) donor cell and an F(-) recipient. Expression of the transfer genes is tightly controlled by a number of factors, including the following plasmid-encoded regulatory proteins: TraJ, the primary activator of the 33-kb tra operon, and the autoregulators TraM and TraY. Here, we demonstrate that the host RNA binding protein, Hfq, represses TraJ and TraM synthesis by destabilizing their respective mRNAs. Mating assays and immunoblot analyses for TraM and TraJ showed that transfer efficiency and protein levels increased in host cells containing a disruption in hfq compared to wild-type cells in stationary phase. The stability of transcripts containing a putative Hfq binding site located in the intergenic untranslated region between traM and traJ was increased in hfq mutant donor cells, suggesting that Hfq destabilizes these transcripts. Electrophoretic mobility shift assays demonstrated that Hfq specifically binds this region but not the antisense RNA, FinP, encoded on the opposite strand. Together, these findings indicate that Hfq regulates traM and traJ transcript stability by a mechanism separate from FinOP-mediated repression.

The multifunctional plant viral suppressor of gene silencing P19 interacts with itself and an RNA binding host protein

Tomato bushy stunt virus (TBSV) is an RNA plant virus encoding a protein of approximately 19 kDa (P19) that is involved in various activities important for pathogenicity, including virus transport and suppression of gene silencing. In this study, we provide evidence in vivo and in vitro that P19 specifically interacts with itself to predominantly form dimers, and with a novel host protein, Hin19. Hin19 has a high degree of similarity with a class of RNA-binding proteins of which many are involved in RNA processing. The binding of P19 to itself and to Hin19 both depend on a structurally important central region of P19 that was previously shown critical for its biological function in plants. Our findings provide evidence for a model in which virus spread through suppression of defense-related gene silencing involves the formation of a complex that includes P19 dimers and a newly identified host RNA-binding protein.

The multifunctional plant viral suppressor of gene silencing P19 interacts with itself and an RNA binding host protein

Tomato bushy stunt virus (TBSV) is an RNA plant virus encoding a protein of approximately 19 kDa (P19) that is involved in various activities important for pathogenicity, including virus transport and suppression of gene silencing. In this study, we provide evidence in vivo and in vitro that P19 specifically interacts with itself to predominantly form dimers, and with a novel host protein, Hin19. Hin19 has a high degree of similarity with a class of RNA-binding proteins of which many are involved in RNA processing. The binding of P19 to itself and to Hin19 both depend on a structurally important central region of P19 that was previously shown critical for its biological function in plants. Our findings provide evidence for a model in which virus spread through suppression of defense-related gene silencing involves the formation of a complex that includes P19 dimers and a newly identified host RNA-binding protein.

Patterns for epilepsy care

<h3>ABSTRACT</h3> Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19. SARS-CoV-2 relies on cellular RNA-binding proteins (RBPs) to replicate and spread, although which RBPs control SARS-CoV-2 infection remains largely unknown. Here, we employ a multi-omic approach to identify systematically and comprehensively which cellular and viral RBPs are involved in SARS-CoV-2 infection. We reveal that the cellular RNA-bound proteome is remodelled upon SARS-CoV-2 infection, having widespread effects on RNA metabolic pathways, non-canonical RBPs and antiviral factors. Moreover, we apply a new method to identify the proteins that directly interact with viral RNA, uncovering dozens of cellular RBPs and six viral proteins. Amongst them, several components of the tRNA ligase complex, which we show regulate SARS-CoV-2 infection. Furthermore, we discover that available drugs targeting host RBPs that interact with SARS-CoV-2 RNA inhibit infection. Collectively, our results uncover a new universe of host-virus interactions with potential for new antiviral therapies against COVID-19.