Project description:To find out differently expressed circRNAs during Orf virus infection of GSF cells and their potential roles in response to ORFV infection
Project description:Contagious ecthyma (Orf) is a contagious disease with worldwide distribution, caused by the epitheliotropic Orf virus (ORFV), a member of the genus Parapoxvirus. In the current study, we collected the oral mucosa tissues samples (T0, T3, T7 and T15) from sheep at 0, 3, 7 and 15 days post ORFV infection, respectively. To explore the changes of comprehensive transcriptome of host cells from oral mucosa tissues post ORFV infection, the RNA-seq transcriptome comparisons were performed on these samples. It showed that 1928, 3219 and 2646 differentially expressed genes (DEGs) were identified among T3 vs. T0, T7 vs. T0, T15 vs. T0 respectively. Through Gene Ontology (GO) analyses of the DEGs from these comparisons, it revealed that ORFV provoked the vigorous immune response of the host cells during the early stage of infection. Moreover, GO and network analysis revealed that positive and negative regulative mechanisms of apoptosis worked as whole in the host cells, in order to reach a homeostasis of oral mucosa tissues.
Project description:Bacterial mRNAs are organized into operons consisting of discrete open reading frames (ORFs) in a single polycistronic mRNA. Individual ORFs on the mRNA are differentially translated, with rates varying as much as 100-fold. The signals controlling differential translation are poorly understood. Our genome-wide mRNA secondary structure analysis indicated that operonic mRNAs are comprised of ORF-wide units of secondary structure that vary across ORF boundaries such that adjacent ORFs on the same mRNA molecule are structurally distinct. ORF translation rate is strongly correlated with its mRNA structure in vivo, and correlation persists, albeit in a reduced form, with its structure when translation is inhibited and with that of in vitro refolded mRNA. These data suggests that intrinsic ORF mRNA structure encodes a rough blueprint for translation efficiency. This structure is then amplified by translation, in a self-reinforcing loop, to provide the structure that ultimately specifies the translation of each ORF.
Project description:The M2-2 protein from the respiratory syncytial virus (RSV) is a 10 kDa protein expressed by the second ORF of the viral gene M2. During infection, M2-2 has been described as the polymerase cofactor responsible for promoting genome replication. This function was first inferred by infection with a mutant virus lacking the M2-2 ORF, in which viral genome presented delayed accumulation in comparison to wild-type virus. In accordance with this phenotype, it has been recently shown that M2-2 promotes changes in interactions between the polymerase and other viral proteins at early stages of infection. Despite its well explored role in the regulation of the polymerase activity, little has been made to investigate the relationship of M2-2 with cellular proteins. In fact, previous reports showed poor recruitment of M2-2 to viral structures, with the protein being mainly localized to the nucleus and cytoplasmic granules. To unravel which other functions M2-2 exerts during infection, we expressed the protein in HEK293T cells and performed proteomic analysis of co-immunoprecipitated partners, identifying enrichment of proteins involved with regulation of translation, protein folding and mRNA splicing. In approaches based on these data, we found that M2-2 expression downregulates eiF2α phosphorylation and inhibits stress granules assembly under arsenite induction. In addition, we also verified that M2-2 inhibits translation initiation, and is targeted for proteasome degradation, being localized to granules composed by defective ribosomal products at the cytoplasm. These results suggest that besides its functions in the regulation of genome replication, M2-2 may exert additional functions to contribute to successful RSV infection.