Project description:Complex functional coupling exists between transcriptional elongation and pre-mRNA alternative splicing. Pausing sites and changes in the rate of transcription by RNAPII may therefore have a fundamental impact in the regulation of alternative splicing. Here, we show that the elongation and splicing-related factor TCERG1 regulates alternative splicing of the apoptosis gene Bcl-x in a promoter-dependent manner. TCERG1 promotes the splicing of the short isoform of Bcl-x (Bcl-xs) through the SB1 regulatory element located in the first half of exon 2. Consistent with these results, we show evidence for in vitro and in vivo interaction of TCERG1 with the Bcl-x pre-mRNA. Transcription profile analysis reveals that the RNA sequences required for the effect of TCERG1 on Bcl-x alternative splicing coincide with a putative polymerase pause site. Furthermore, TCERG1 modifies the impact of a slow polymerase on Bcl-x alternative splicing. In support of a role for an elongation mechanism in the transcriptional control of Bcl-x alternative splicing, we found that TCERG1 modifies the amount of pre-mRNAs generated at distal regions of the endogenous Bcl-x. Most importantly, TCERG1 affects the rate of RNAPII transcription of endogenous human Bcl-x. We propose that TCERG1 modulates the elongation rate of RNAPII to relieve pausing, thereby activating the pro-apoptotic Bcl-xS 5’ splice site. ChIP-Seq
Project description:To investigate the molecular and physiological functions of SWAP1 in light signaling. We show that SWAP1 modulates global gene expression and alternative splicing both under dark and red light treated conditions
Project description:Alternative splicing is a mechanism for increasing the protein variety of a limited number of genes. Studies have shown that aberrant regulations of the alternative splicing of apoptotic gene transcripts may contribute to the development of cancer. In this study, we isolated 4β-Hydroxywithanolide E (4bHWE) from the traditional herb Physalis peruviana, and analyzed its biological effects in cancer cells. The results demonstrated that 4bHWE modulates the alternative splicing of apoptotic genes (e.g., HIPK3, SMAC/DIABLO, and SURVIVIN), changes the expression level of splicing factors (e.g., hnRNP C1/C2, ASF/SF2, SRp20, and SRp55), and induces histone tail posttranslational modifications (e.g., H3K27me1, H3K27me2, H3K36me3, and H3K79me1). Pretreatment with okadaic acid to inhibit protein phosphatase-1 could partly relieve the effects of 4bHWE on the alternative splicing of HIPK3 and SMAC/DIABLO transcripts, as well as on the dephosphorylation of ASF/SF2. Genome-wide detection of alternative splicing further indicated that several other apoptosis-related genes are also regulated by 4bHWE, including APAF1, CARP-1, and RIPK1. Moreover, we extended our study to apoptosis-associated molecules, detecting an increasing level of CASPASE-3 activity and cleavage of poly ADP-ribose polymerase in 4bHWE-induced apoptosis. Furthermore, in vivo experiments showed that the treatment of tumor-bearing mice with 4bHWE resulted in a marked decrease of tumor size and weight. Taken together, this study is the first to show that 4bHWE affects alternative splicing through the modulations of splicing factors, providing a novel view of the antitumor mechanism of 4bHWE.
Project description:Introduction: Neuroendocrine prostate cancer (NEPC) is an aggressive subtype of prostate cancer, exhibiting rapid progression and is unresponsive to hormone therapy. Reliable prognostic assays and more effective treatments are critically required. However, the research of NEPC has been hampered by a lack of clinically relevant in vivo models. Recently, we successfully developed a first-in-field patient tissue-derived xenograft model of complete neuroendocrine transdifferentiation from prostate adenocarcinoma. By comparing gene expression profiles of the parental adenocarcinoma line (LTL331) and the NEPC subline (LTL331R), we identified DEK, a gene not previously reported in prostate cancer, as a potential biomarker and target for NEPC. Methods: DEK protein expression in patient tissue-derived xenograft models and clinical samples was assessed by immunohistochemistry. The function of DEK was determined by siRNA-induced reduction of DEK expression in PC-3 cells, a cell line with NEPC characteristics, followed by functional assays and gene expression profiling analysis. Results: Elevated DEK protein expression was observed in all clinical NEPC cases, which is distinct from their benign counterparts (0%), hormonal naïve prostate cancer (2.45%) and castration resistant prostate cancer (29.55%). Increased DEK expression is an independent clinical risk factor and is associated with shorter disease free survival in hormonal naïve prostate cancer patients. Reduction of DEK expression in PC-3 cells led to a marked reduction in cell proliferation, cell migration and invasion. Conclusions: The results suggest that DEK may play an important role in the progression of prostate cancer, especially NEPC and provide a potential biomarker to aid risk stratification of prostate cancer and a novel therapeutic target for treating NEPC. The function of DEK was determined by siRNA-induced reduction of DEK expression in PC-3 cells, a cell line with NEPC characteristics, followed by functional assays and gene expression profiling analysis.
Project description:CC-671 has been identified as an inhibitor of Cdc2-like kinase 2 (CLK2) and TTK in direct enzyme assays. CLK2 is a member of the CLK family that phosphorylates serine- and arginine-rich (SR) proteins of the spliceosomal complex as part of a regulatory mechanism for control of pre-mRNA splicing. SR proteins are a family of small nuclear ribonucleoprotein particle (snRNP) splicing factors involved in constitutive and alternative splicing. Monitoring specific phospho-biomarkers of CLK2 demonstrated that CC-671 inhibited phosphorylation of CLK2 substrates in cancer cells with mean IC50 of 549 nM in the triple negative breast cancer (TNBC) line CAL51. In this study, RNA sequencing approach was used to quantify the impact of CC-671 treatment on gene transcription and global alternative splicing in CAL51 cells. Differential exon usage analysis demonstrated that CC-671 changed alternative splicing of many genes. In addition, different sets of genes are impacted by CC-671 at both the alternative splicing and mRNA expression. Genes impacted by alternative splicing shared a set of common pathways with genes altered by mRNA expression. This result indicates that CC-671 regulates transcription via both gene expression and alternative splicing mechanisms.
Project description:Alternative splicing profiling of apopotosis related genes in human HeLa cells (cervical cancer cell line) transfected with a plasmid expressing shRNAs targetting p68 helicase (DDX5, DEAD (Asp-Glu-Ala-Asp) box polypeptide 5) cloned into the pSuper expression vector compared to empty vector. Keywords: treated vs. untreated comparison; alternative splicing
Project description:We used Affymetrix GeneChipM-BM-. Human Exon 1.0 ST Arrays to identify alternative splicing events in 15 samples of PDAC compared to 6 non-tumor samples. Several commercial and open source software approaches for the analysis of differential splicing were tested and a subset of overlapping results was validated using RT-PCR and sequencing. Splicing variants could be validated in several genes closely related to cancer. Pathway analysis of genes predicted to be alternatively spliced revealed an enrichment of genes in categories closely related to cell-cell interactions and kinase activity. 15 samples of pancreatic ductal adenocarcinoma and 6 non tumor pancreatic samples were analyzed for alternative splicing events