Identifying HIV RNA splice variant protein interactomes using HyPRMS
Ontology highlight
ABSTRACT: Submitting raw mass spec files for the protein interactomes of HIV-1 unspliced, partially spliced and completely spliced RNAs as determined by HyPR-MS.
Project description:Peptides generated by proteasome-catalyzed splicing of non-contiguous amino acid sequences have been shown to constitute a source of non-templated human leukocyte antigen class I (HLA-I) epitopes, but their role in pathogen-specific immunity remains unknown. CD8+ T cells are key mediators of human immunodeficiency virus type 1 (HIV-1) control, and identification of novel epitopes to enhance targeting of infected cells is a priority for prophylactic and therapeutic strategies. To explore the contribution of proteasome-catalyzed peptide splicing (PCPS) to HIV-1 epitope generation, we developed a broadly-applicable mass spectrometry-based discovery workflow that we employed to identify spliced HLA-I-bound peptides on HIV-infected cells. We demonstrate that HIV-1-derived spliced peptides comprise a novel, but relatively minor, component of the HLA-I-bound viral immunopeptidome. Although spliced HIV-1 peptides may elicit CD8+ T cell responses relatively infrequently during infection, CD8+ T cells primed by partially-overlapping contiguous epitopes in HIV-infected individuals were able to cross-recognize spliced viral peptides, suggesting a potential role for PCPS in restricting HIV-1 escape pathways. Vaccine-mediated priming of responses to spliced HIV-1 epitopes could thus provide a novel means of exploiting epitope targets typically under-utilized during natural infection.
Project description:HIV-1 latency results from a combination of tightly regulated molecular processes that act at distinct steps of HIV-1 gene expression. In an effort to elucidate the molecular players that govern viral latency, we previously performed a dCas9 chromatin immunoprecipitation coupled with mass spectrometry (Catchet-MS) and identified proteins bound differentially to the latent LTR that putatively promote HIV-1 latency. Here we characterize the Catchet-MS identified PCI domain-containing 2 (PCID2) protein to play a dual role in promoting HIV-1 latency by enforcing both HIV-1 transcription repression as well as post-transcriptional blocks. PCID2 bound the latent HIV-1 LTR and repressed transcription initiation during latency. Depletion of PCID2 remodeled the chromatin landscape at the HIV-1 promoter and resulted in transcriptional activation and reversal of latency. Immunoprecipitation coupled to Mass Spectrometry identified the PCID2 interacting proteins to include members of the spliceosome and other splicing regulators, including negative regulators of viral RNA alternative splicing. PCID2 depletion resulted in over-splicing of intron-containing HIV-1 RNA and mis-regulated expression of vRNA splice variants. Finally, consistent with its role in NXF1-mediated nascent RNA nucleocytoplasmic export as part of the TREX2 complex, PCID2 modulates export of completely spliced vRNA. In summary, we demonstrate that PCID2 is a previously unidentified factor involved in HIV-1 latency regulation which plays a dual role in blocking HIV-1 gene expression by acting on transcription initiation as well as viral RNA processing.
Project description:Circular RNAs (circRNAs) are a class of transcripts that are formed when portions of a pre-mRNA molecule are spliced together in a closed loop. Here, we discover a novel HIV-1-encoded viral circRNA present in patient-derived plasma and infected T-cell lines, demonstrating that an RNA retrovirus can generate circRNAs. This HIV-1-encoded circRNA is packaged within HIV-1 virions, binds the HIV-1 Tat protein, and enhances transcription from the HIV-1 promoter. Our study sheds lights on a previously overlooked aspect of HIV-1 transcription and presents interactions between viral proteins and viral circRNAs as novel mechanisms underlying viral pathogenesis.
Project description:RNA-protein interactions are central to biological regulation. Cross-linking immunoprecipitation (CLIP)-seq is a powerful tool for genome-wide interrogation of RNA-protein interactomes, but current CLIP methods are limited by challenging biochemical steps and fail to detect many classes of noncoding and non-human RNAs. Here we present FAST-iCLIP, an integrated pipeline with improved CLIP biochemistry and an automated informatic pipeline for comprehensive analysis across protein coding, noncoding, repetitive, retroviral, and non-human transcriptomes. FAST-iCLIP of Poly-C binding protein 2 (PCBP2) showed that PCBP2 bound CU-rich motifs in different topologies to recognize mRNAs and noncoding RNAs with distinct biological functions. FAST-iCLIP of PCBP2 in hepatitis C virus-infected cells enabled a joint analysis of the PCBP2 interactome with host and viral RNAs and their interplay. These results show that FAST-iCLIP can be used to rapidly discover and decipher mechanisms of RNA-protein recognition across the diversity of human and pathogen RNAs. Characterization of non-coding and pathogen RNA-protein interactions using an automated computational pipeline and improved iCLIP biochemistry
Project description:Intracellular Tat101 deregulated the expression of spliceosome core components, such as SF3B2, SF3A1, SFPQ, PCBP1, SYNCRIP, YBX1 and HSP8A/HSP7C, and thus likely the splicing pathway. Viral splicing experiments showed that Tat101 favored the expression of viral unspliced RNA, which are used at the late steps of the viral cycle, rather than spliced RNAs allowing the progression of HIV-1 replication.
Project description:RNA-protein interactions are central to biological regulation. Cross-linking immunoprecipitation (CLIP)-seq is a powerful tool for genome-wide interrogation of RNA-protein interactomes, but current CLIP methods are limited by challenging biochemical steps and fail to detect many classes of noncoding and non-human RNAs. Here we present FAST-iCLIP, an integrated pipeline with improved CLIP biochemistry and an automated informatic pipeline for comprehensive analysis across protein coding, noncoding, repetitive, retroviral, and non-human transcriptomes. FAST-iCLIP of Poly-C binding protein 2 (PCBP2) showed that PCBP2 bound CU-rich motifs in different topologies to recognize mRNAs and noncoding RNAs with distinct biological functions. FAST-iCLIP of PCBP2 in hepatitis C virus-infected cells enabled a joint analysis of the PCBP2 interactome with host and viral RNAs and their interplay. These results show that FAST-iCLIP can be used to rapidly discover and decipher mechanisms of RNA-protein recognition across the diversity of human and pathogen RNAs.
Project description:Here we identify -KTS, a major alternatively spliced isoform of the Wilms’ tumor suppressor WT1, as a key determinant of female sex determination.
Project description:To study the dynamics of RNA interactomes, RIC-seq was performed on several biological replicates of colorectal cancer patients, each including colorectal adenomas, cancerous tissues, and tissues distal to cancer
Project description:MiRNAs and other small noncoding RNAs (sncRNAs) are key players in post-transcriptional gene regulation. HIV-1 derived small noncoding RNAs (sncRNAs) have been described in HIV-1 infected cells, but their biological functions still remain to be elucidated. Here, we approached the question whether viral sncRNAs may play a role in the RNA interference (RNAi) pathway or whether viral mRNAs are targeted by cellular miRNAs in human monocyte-derived macrophages (MDM). The incorporation of viral sncRNAs and/or their target RNAs into RNA-induced silencing complex was investigated using photoactivatable ribonucleoside-induced cross-linking and immunoprecipitation (PAR-CLIP) as well as high-throughput sequencing of RNA isolated by cross-linking immunoprecipitation (HITS-CLIP), which capture Argonaute2-bound miRNAs and their target RNAs. HIV-1 infected monocyte-derived macrophages (MDM) were chosen as target cells, as they have previously been shown to express HIV-1 sncRNAs. In addition, we applied small RNA deep sequencing to study differential cellular miRNA expression in HIV-1 infected versus non-infected MDMs. PAR-CLIP and HITS-CLIP data demonstrated the absence of HIV-1 RNAs in Ago2-RISC, although the presence of a multitude of HIV-1 sncRNAs in HIV-1 infected MDMs was confirmed by small RNA sequencing. Small RNA sequencing revealed that 1.4% of all sncRNAs were of HIV-1 origin. However, neither HIV-1 derived sncRNAs nor putative HIV-1 target sequences incorporated into Ago2-RISC were identified, suggesting that HIV-1 sncRNAs are not involved in the canonical RNAi pathway nor is HIV-1 targeted by this pathway in HIV-1 infected macrophages.
Project description:Analysis of RISC bound short (s)RNAs in cells infected with HIV-1 reveals a contribution of 6mer seed toxicity to HIV-1 induced cytopathicity