Project description:Unlike in Asia and Latin America, Plasmodium vivax infections were rare in Sub-Saharan Africa due to the absence of the Duffy blood group antigen (Duffy Antigen), the only known erythrocyte receptor for the P. vivax merozoite invasion ligand, Duffy Binding Protein 1 (DBP1). However, P. vivax infections have been documented in Duffy-negative individuals throughout Africa, suggesting that P. vivax may use ligands other than DBP1 to invade Duffy-negative erythrocytes through other receptors. To identify potential P. vivax ligands, we compared parasite gene expression in Saimiri and Aotus monkey erythrocytes infected with P. vivax Salvador I (Sal I). DBP1 binds Aotus but does not bind to Saimiri erythrocytes, and thus P. vivax Sal I must invade Saimiri erythrocytes independently of DBP1. Comparing RNA sequencing (RNAseq) data for late stage infections in Saimiri and Aotus erythrocytes when invasion ligands are expressed, we identified genes that belong to tryptophan-rich antigen and MSP3 families that were more abundantly expressed in Saimiri infections as compared to Aotus infections. These genes may encode potential ligands responsible for P. vivax infections of Duffy-negative Africans.
Project description:We report the discovery of six novel miRNAs expressed by Herpesvirus saimiri (strain A11). These miRNAs are generated by a non-canonical biogenesis pathway that does not require the Microprocessor complex. Examination of one sample prepared from common marmoset (Callithrix jacchus) T cells latently infected with Hespesvirus saimiri (strain A11).
Project description:We report the discovery of six novel miRNAs expressed by Herpesvirus saimiri (strain A11). These miRNAs are generated by a non-canonical biogenesis pathway that does not require the Microprocessor complex.
Project description:Population of viral small RNAs expressed in common marmoset (Callithrix jacchus) T cells latently infected with Herpesvirus saimiri (strain A11)
Project description:In latently-infected marmoset T cells, Herpesvirus saimiri (HVS) expresses six microRNAs (known as miR-HSURs). The viral miR-HSURs are processed from chimeric primary transcripts, each containing a noncoding U-rich RNA (HSUR) and a pre-miRNA hairpin. To uncover functions of miR-HSURs, we identified mRNA targets in infected cells using High-Throughput Sequencing of RNA Isolated by Crosslinking Immunoprecipitation (HITS-CLIP). HITS-CLIP revealed hundreds of robust Argonaute (Ago) binding sites mediated by miR-HSURs in the host genome, but few in the HVS genome. Gene Ontology analysis showed that several pathways regulating the cell cycle are enriched among cellular targets of miR-HSURs. Interestingly, miR-HSUR4-3p represses expression of the p300 transcriptional co-activator by binding the open reading frame of its mRNA. miR-HSUR5-3p directly regulates BiP, an endoplasmic reticulum (ER) localized chaperone facilitating maturation of the Major Histocompatibility Complex I (MHC I) and the antiviral response. miR-HSUR5-3p also robustly downregulates WEE1, a key negative regulator of cell-cycle progression, leading to reduced phosphorylation of its substrate cyclin-dependent kinase (Cdk1). Consistently, inhibition of miR-HSUR5-3p in HVS-infected cells decreases their proliferation. Together, our results shed light on the roles of viral miRNAs in cellular transformation and viral latency.
