Project description:Primary effusion lymphoma (PEL) is caused by Kaposi's sarcoma-associated herpesvirus (KSHV) and frequently also harbors Epstein-Barr virus (EBV). The expression of KSHV- and, often, EBV-encoded microRNAs (miRNAs) in PELs suggests a role for these miRNAs in viral latency and lymphomagenesis. Here we report the direct and transcriptome-wide identification of miRNA target sites for all miRNAs expressed in PEL cell lines. The resulting dataset revealed that KSHV miRNAs directly target more than 2000 cellular mRNAs encoding proteins that function in pathways with relevance to KSHV pathogenesis. Moreover, ~50% of these mRNAs are also targeted by EBV miRNAs, via distinct binding sites. In addition to a known viral analog of miR-155, we show that KSHV encodes a viral miRNA that mimics cellular miR-142-3p function. In summary, these experiments identify an extensive list of mRNAs targeted by KSHV miRNAs and indicate that these are likely to strongly influence viral replication and pathogenesis. small RNA sequencing, 3 samples Ago2 (EIF2C2) PAR-CLIP, 2 samples
Project description:This study compares changes in gene expression induced by four interrelated miRNAs with similar but staggered 5'-ends: miR-142-3p, miR-142-3p-1, miR-K10a, and miR-K10a+1. miR-K10a and miR-K10a+1 are co-expressed by the Kaposi's sarcoma-associated herpesvirus. Total RNA was harvested from HEK293 cells transfected with individual miRNAs including a negative control miRNA mimic.
Project description:This study compares changes in gene expression induced by four interrelated miRNAs with similar but staggered 5'-ends: miR-142-3p, miR-142-3p-1, miR-K10a, and miR-K10a+1. miR-K10a and miR-K10a+1 are co-expressed by the Kaposi's sarcoma-associated herpesvirus.
Project description:MicroRNAs are small, non-coding RNAs that post-transcriptionally regulate gene expression by binding to 3âUTRs of target mRNAs. Kaposiâs sarcoma-associated herpesvirus (KSHV), a virus linked to malignancies including primary effusion lymphoma (PEL), encodes 12 miRNA genes, but only a few regulatory targets are known. We found that KSHV-miR-K12-11 shares 100% seed-sequence homology with hsa-miR-155, a miRNA frequently found up-regulated in lymphomas and critically important for B cell development. Based on this seed-sequence homology, we hypothesized that both miRNAs regulate a common set of target genes and as a result, could have similar biological activities. Examination of five PEL lines showed that PELs do not express miR-155, but do express high levels of miR-K12-11. Bioinformatics tools predicted the transcriptional repressor BACH-1 to be targeted by both miRNAs and ectopic expression of either miR-155 or miR-K12-11 inhibited a BACH-1 3'UTR containing reporter. . Furthermore, BACH-1 protein levels are low in cells expressing either miRNA. Gene expression profiling of miRNA-expressing stable cell lines revealed 66 genes that were commonly down-regulated. For select genes, miRNA targeting was confirmed by reporter assays. Thus, based on our in silico predictions, reporter assays, and expression profiling data, miR-K12-11 and miR-155 regulate a common set of cellular targets. Given the role of miR-155 during B cell maturation, we speculate that miR-K12-11 may contribute to the distinct developmental phenotype of PEL cells, which are blocked in a late stage of B cell development. Together, these findings indicate that KSHV miR-K12-11 is an ortholog of miR-155. Experiment Overall Design: 12 samples, 4 experiemental (miR-155 ), 4 experimental (miR-K12-11) and 4 reference controls (pCDNA3.1)
Project description:Primary effusion lymphoma (PEL) is caused by Kaposi's sarcoma-associated herpesvirus (KSHV) and frequently also harbors Epstein-Barr virus (EBV). The expression of KSHV- and, often, EBV-encoded microRNAs (miRNAs) in PELs suggests a role for these miRNAs in viral latency and lymphomagenesis. Here we report the direct and transcriptome-wide identification of miRNA target sites for all miRNAs expressed in PEL cell lines. The resulting dataset revealed that KSHV miRNAs directly target more than 2000 cellular mRNAs encoding proteins that function in pathways with relevance to KSHV pathogenesis. Moreover, ~50% of these mRNAs are also targeted by EBV miRNAs, via distinct binding sites. In addition to a known viral analog of miR-155, we show that KSHV encodes a viral miRNA that mimics cellular miR-142-3p function. In summary, these experiments identify an extensive list of mRNAs targeted by KSHV miRNAs and indicate that these are likely to strongly influence viral replication and pathogenesis.
Project description:Kaposi's sarcoma-associated herpesvirus (KSHV) encodes a viral RNA-binding protein ORF57 that plays an essential role in posttranscriptional regulation of viral gene expression. Ectopice expression of KSHV ORF57 in HEK293T cells was evaluated on its effect on host gene expression in the study, with the cells transfected with an empty vector serving as a control.
Project description:Marek’s disease virus 1 (MDV-1), an oncogenic -herpesvirus that induces T-cell lymphomas in chickens, serves as model system to study transformation by lymphotropic herpesviruses. Like the oncogenic human -herpesviruses Kaposi’s sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV), MDV-1 encodes several viral microRNAs (miRNAs). One MDV-1 miRNA, miR-M4, shares the same “seed” targeting sequence with both a KSHV miRNA, miR-K11, and cellular miR-155. Importantly, miR-M4 plays a critical role in T-cell transformation by MDV-1, while miR-K11 and cellular miR-155 are thought to play key roles in B-cell transformation by KSHV and EBV, respectively. Here, we present an analysis of the mRNAs targeted by viral miRNAs expressed in the chicken T-cell line MSB1, which is naturally coinfected with MDV-1 and the related nonpathogenic virus MDV-2. Our analysis identified>1,000 endogenous mRNAs targeted by miRNAs encoded by each virus, many of which are targeted by both MDV-1 and MDV-2 miRNAs. We present a functional analysis of an MDV-1 gene, RLORF8, targeted by four MDV-1 miRNAs and a cellular gene, encoding interleukin-18 (IL-18) and targeted by both MDV-1 and MDV-2 miRNAs, and show that ectopic expression of either protein in a form resistant to miRNA inhibition results in inhibition of cell proliferation. Finally, we present a restricted list of 9 genes targeted by not only MDV-1 miR-M4 but also KSHV miR-K11 and human miR-155. Given the critical role played by miR-155 seed family members in lymphomagenesis in humans and chickens, these mRNA targets may contain genes whose inhibition plays a conserved role in herpesvirus transformation. PAR-CLIP experiment of MSB1 cells
Project description:Kaposi's sarcoma-associated herpesvirus (KSHV) can efficiently infect and transform primary rat mesenchymal precursor (MM) cells. Regulation of cell cycle progression and apoptosis by KSHV-encoded microRNAs is required for KSHV-induced cellular transformation and tumorigenesis. To determine the roles of KSHV miRs in growth deregulation, we infected MM cells with the KSHV miR cluster deletion mutant and monitored infection by examining green fluorescence protein expression from a cassette inserted in the KSHV genome.