Project description:Role of alternative polyadenylation (APA) in rat brain after vaporized cannabis plant matter (CPM) exposure remains largely undetermined. Our WTTS-seq approach to capture 3'-end of RNAs clearly revealed alternative polyadenylation events responsible for dominantly down-regulates APA expression on Glutamatergic Transcripts in rats after CPM Exposure.
Project description:The tumorigenesis of small intestinal neuroendocrine tumors (NETs) is poorly understood. Recent studies have associated alternative polyadenylation with proliferation, cell transformation and cancer. Polyadenylation is the process in which the pre-mRNA is cleaved at a polyA site and a polyA tail is added. Genes with two or more polyA sites can undergo alternative polyadenylation. This produces two or more distinct mRNA isoforms with different 3M-bM-^@M-^Y untranslated regions. Additionally, alternative polyadenylation can also produce mRNAs containing different 3M-bM-^@M-^Y-terminal coding regions. Therefore, alternative polyadenylation alters both the repertoire and the expression level of proteins. Here we used high-throughput sequencing data to map polyA sites and characterize polyadenylation genome-wide in three small intestinal neuroendocrine tumors and a reference sample. In the tumors sixteen genes showed significant changes of alternative polyadenylation pattern, which lead to either the 3M-bM-^@M-^Y truncation of mRNA coding regions or 3M-bM-^@M-^Y untranslated regions. Among these, 11 genes had been previously associated with cancer, with 4 genes being known tumor suppressors: DCC, PDZD2, MAGI1 and DACT2. We validated the alternative polyadenylation in 3 out of 3 cases with Q-RT-PCR. Our findings suggest that changes of alternative polyadenylation pattern in these 16 genes could be involved in the tumorigenesis of small intestinal neuroendocrine tumors. Furthermore, they also point to alternative polyadenylation as a new target for both diagnostic and treatment of small intestinal neuroendocrine tumors. The identified genes with alternative polyadenylation specific to the small intestinal neuroendocrine tumors could be further tested as diagnostic markers and drug targets for disease prevention and treatment. PolyA-seq profiling of 3 human neuroendocrine tumors compared and pituitary using Direct RNA Sequencing from Helicos Biosciences Technology
Project description:The tumorigenesis of small intestinal neuroendocrine tumors (NETs) is poorly understood. Recent studies have associated alternative polyadenylation with proliferation, cell transformation and cancer. Polyadenylation is the process in which the pre-mRNA is cleaved at a polyA site and a polyA tail is added. Genes with two or more polyA sites can undergo alternative polyadenylation. This produces two or more distinct mRNA isoforms with different 3’ untranslated regions. Additionally, alternative polyadenylation can also produce mRNAs containing different 3’-terminal coding regions. Therefore, alternative polyadenylation alters both the repertoire and the expression level of proteins. Here we used high-throughput sequencing data to map polyA sites and characterize polyadenylation genome-wide in three small intestinal neuroendocrine tumors and a reference sample. In the tumors sixteen genes showed significant changes of alternative polyadenylation pattern, which lead to either the 3’ truncation of mRNA coding regions or 3’ untranslated regions. Among these, 11 genes had been previously associated with cancer, with 4 genes being known tumor suppressors: DCC, PDZD2, MAGI1 and DACT2. We validated the alternative polyadenylation in 3 out of 3 cases with Q-RT-PCR. Our findings suggest that changes of alternative polyadenylation pattern in these 16 genes could be involved in the tumorigenesis of small intestinal neuroendocrine tumors. Furthermore, they also point to alternative polyadenylation as a new target for both diagnostic and treatment of small intestinal neuroendocrine tumors. The identified genes with alternative polyadenylation specific to the small intestinal neuroendocrine tumors could be further tested as diagnostic markers and drug targets for disease prevention and treatment.
Project description:Disruption of alternative splicing frequently causes or contributes to human diseases and disorders. Consequently, there is a need for efficient and sensitive reporter assays capable of screening chemical libraries for compounds with efficacy in modulating important splicing events. Here, we describe a screening workflow employing dual Nano and Firefly luciferase alternative splicing reporters that affords highly efficient, sensitive, and linear detection of small molecule responses. Applying this system to a screen of ~95,000 small molecules, we identify compounds that selectively activate or repress a neuronal microexon network that is frequently disrupted in autism and overexpressed in neuroendocrine cancers. Remarkably, among the most potent and selective activating compounds are histone deacetylase (HDAC) inhibitors. We thus describe a high-throughput screening system for candidate splicing therapeutics, a resource of small molecule modulators of microexons, and insight into the mode of action and potential utility of HDAC inhibitors in the context of neurological disorders.
Project description:Identification of newer compounds to modulate dendritic cell functions. Total RNA obtained from bone marrow-derived dendritic cells treated for 6 hours with small chemical compounds or vehicle alone in the presence or absence of lipopolysaccharide (LPS).
Project description:Stem cell differentiation involves a global increase in protein synthesis to meet the demands of specialized cell types. However, the molecular mechanisms underlying this translational burst and the involvement of initiation factors remains largely unknown. Here, we investigate the roles of eukaryotic initiation factor 3 (eIF3) in early differentiation of human pluripotent stem cell (hPSC)-derived neural progenitor cells (NPCs). Using Quick-irCLIP and alternative polyadenylation (APA)-Seq, we show eIF3 crosslinks to many neurologically relevant mRNAs in NPCs. Our data reveal eIF3 predominantly interacts with 3’ untranslated region (3’-UTR) termini of multiple mRNA isoforms, adjacent to the poly(A) tail. High eIF3 crosslinking at 3’-UTR termini of mRNAs correlates with high translational activity, as determined by ribosome profiling. We identify the transcriptional regulator inhibitor of DNA binding 2 (ID2) mRNA as a case in which active translation levels and eIF3 crosslinking are dramatically increased upon early NPC differentiation. Furthermore, we find that eIF3 engagement at 3’-UTR ends is dependent on polyadenylation. The results presented here show that eIF3 engages with 3’-UTR termini in highly translated mRNAs, supporting a role of mRNA circularization in the mechanisms governing mRNA translation in NPCs.
Project description:Cancer cells often co-opt post-transcriptional regulatory mechanisms to achieve pathologic expression of gene networks that drive metastasis. Translational control is a major regulatory hub in oncogenesis, however its effects on cancer progression remain poorly understood. To address this, we used ribosome profiling to compare genome-wide translation efficiencies of poorly and highly metastatic breast cancer cells and patient-derived xenografts. We developed novel regression-based methods to analyze ribosome profiling and alternative polyadenylation data, and identified HNRNPC as a translational controller of a specific mRNA regulon. Mechanistically, HNRNPC, in concert with PABPC4, binds near to poly(A) signals, thereby governing the alternative polyadenylation of a set of mRNAs. We found that HNRNPC and PABPC4 are downregulated in highly metastatic cells, which causes HNRNPC-bound mRNAs to undergo 3’ UTR lengthening and subsequently, translational repression. We showed that modulating HNRNPC expression impacts the metastatic capacity of breast cancer cells in xenograft mouse models. We also found that a small molecule, previously shown to induce a distal-to-proximal poly(A) site switching, counteracts the HNRNPC-PABPC4 driven deregulation of alternative polyadenylation and decreases the metastatic lung colonization by breast cancer cells in vivo.
Project description:Exploring the involvement of AGO2 in regulating alternative polyadenylation, by analyzing all 3' end transcript variants using 3'RNA-seq data.
Project description:Cancer cells often co-opt post-transcriptional regulatory mechanisms to achieve pathologic expression of gene networks that drive metastasis. Translational control is a major regulatory hub in oncogenesis, however its effects on cancer progression remain poorly understood. To address this, we used ribosome profiling to compare genome-wide translation efficiencies of poorly and highly metastatic breast cancer cells and patient-derived xenografts. We developed novel regression-based methods to analyze ribosome profiling and alternative polyadenylation data, and identified HNRNPC as a translational controller of a specific mRNA regulon. Mechanistically, HNRNPC, in concert with PABPC4, binds near to poly(A) signals, thereby governing the alternative polyadenylation of a set of mRNAs. We found that HNRNPC and PABPC4 are downregulated in highly metastatic cells, which causes HNRNPC-bound mRNAs to undergo 3’ UTR lengthening and subsequently, translational repression. We showed that modulating HNRNPC expression impacts the metastatic capacity of breast cancer cells in xenograft mouse models. We also found that a small molecule, previously shown to induce a distal-to-proximal poly(A) site switching, counteracts the HNRNPC-PABPC4 driven deregulation of alternative polyadenylation and decreases the metastatic lung colonization by breast cancer cells in vivo.