Project description:PRMT1 is highly expressed in breast tumors, and has been suggested to play a vital role in breast tumorigenesis, but the underlying molecular mechanisms remain to be fully characterized. Here, we reveal that PRMT1 exhibits a wide-spreading role in RNA alternative splicing based on transcriptome analysis, with a preference for exon inclusion in a large cohort of oncogenic genes. Profiling PRMT1 methylome reveals that the arginine/serine-rich splicing factor SRSF1 is heavily arginine-methylated by PRMT1, which is critical for SRSF1 phosphorylation, SRSF1 binding with RNA, and PRMT1-induced exon inclusion. In breast tumors, the overexpression of PRMT1 is associated with high levels of SRSF1 arginine methylation and aberrant exon inclusion in those oncogenic genes. Accordingly, PRMT1-mediated SRSF1 methylation and exon inclusion events are found to be critical for the malignant behaviors of breast cancer cells. Furthermore, we identified and characterized a selective PRMT1 inhibitor iPRMT1, which is potent in inhibiting PRMT1-mediated SRSF1 methylation and exon inclusion events, and breast cancer cell growth both in vitro and in vivo. Combination treatment with iPRMT1 and inhibitor targeting SRSF1 phosphorylation, SPHINX31 or SRPIN340, exhibits synergistic effects on suppressing breast cancer cell growth, strengthening the cross-talk between arginine methylation and phosphorylation in SRSF1. In conclusion, our data uncover a key mechanism underlying PRMT1-mediated gene alternative splicing, demonstrating targeting PRMT1 has great potential to treat breast cancer in clinic.
Project description:We describe the application of a new microarray platform, which combines information from exon body and splice-junction probes, to analyze the regulation of 3126 alternative splicing events in ten mouse tissues. The details of the methods and algorithms are described in this paper: Revealing global regulatory features of mammalian alternative splicing using a quantitative microarray platform (Molecular Cell, Dec., 2004) Keywords = A new quantitative alternative splicing microarray platform Keywords: other
Project description:Analysis to identify genome-wide differential alternative splicing events in A549 cells in which the levels of the gene SRSF1 were down-regulated with a specific siRNA 9 samples from three independent experiments using A549 cells transfected with lipofectamine alone, scramble siRNA or SRSF1 siRNA
Project description:Abstract: Alternative splicing (AS) plays a major role in the generation of proteomic diversity and in gene regulation. However, the role of the basal splicing machinery in regulating AS remains poorly understood. Here we show that the core snRNP protein SmB/B’ self-regulates its expression by promoting the inclusion of a highly-conserved alternative exon in its own pre-mRNA that targets the spliced transcript for nonsense-mediated mRNA decay (NMD). Depletion of SmB/B’ in human cells results in reduced levels of snRNPs and in a striking reduction in the inclusion levels of hundreds of alternative exons, with comparatively few effects on constitutive exon splicing levels. The affected alternative exons are enriched in genes encoding RNA processing and other RNA binding factors, and a subset of these exons also regulate gene expression by activating NMD. Our results thus demonstrate a role for the core spliceosomal machinery in controlling an exon network that appears to modulate the levels of many RNA processing factors. HeLa cells were transfected with a control non-targeting siRNA pool (siNT), or with siRNA pools designed to knockdown SmB/B' or SRSF1 (also known as SF2/ASF/SFRS1). Sequence reads were aligned to exon-exon junction sequences in a database of EST/cDNA-mined cassette-type alternative splicing events. Processed data files (.bed and .txt) provided as supplementary files on the Series record. Processed data file build information: hg18.
Project description:We describe the application of a new microarray platform, which combines information from exon body and splice-junction probes, to analyze the regulation of 3126 alternative splicing events in ten mouse tissues. The details of the methods and algorithms are described in this paper: Revealing global regulatory features of mammalian alternative splicing using a quantitative microarray platform (Molecular Cell, Dec., 2004) Keywords = A new quantitative alternative splicing microarray platform
Project description:Alternative pre-mRNA splicing is a prevalent mechanism in mammals that promotes proteomic diversity, including expression of cell-type specific protein isoforms. We characterized a role for RBM38 (RNPC1) in regulation of alternative splicing during late erythroid differentiation. We used an affymetrix human exon junction (HJAY) splicing microarray to identify a panel of RBM38-regulated alternatively spliced transcripts. Using microarray databases, we noted high RBM38 expression levels in CD71+ erythroid cells and thus chose to examine RBM38 expression during erythroid differentiation of human hematopoietic stem cells, detecting enhanced RBM38 expression during late erythroid differentiation. In differentiated erythroid cells, we validated a subset of RBM38-regulated splicing events and determined that RBM38 regulates activation of Protein 4.1R (EPB41) exon 16 during late erythroid differentiation. Using Epb41 minigenes, Rbm38 was found to be a robust activator of exon 16 splicing. To further address the mechanism of RBM38-regulated alternative splicing, a novel mammalian protein expression system, followed by SELEX-Seq, was used to identify a GU-rich RBM38 binding motif. Lastly, using a tethering assay, we determined that RBM38 can directly activate splicing when recruited to a downstream intron. Together, our data support the role of RBM38 in regulating alternative splicing during erythroid differentiation. siRNA knockdown of RBM38 was perfomed in human MCF-7 breast cancer cells. The efficiency of RBM38 knockdown was monitored by western blot using an RBM38 antibody (Santa Cruz Biotechnology, SC-85873). We conducted HJAY exon and exon junction array profiling on RNAs from four siRBM38 treated MCF-7 samples vs. four sicontrol treated MCF-7 samples Control / knockdown comparison.
Project description:Alternative pre-messenger RNA splicing impacts development, physiology, and disease, but its regulation in humans is not well understood, partially due to the limited scale to which the expression of specific splicing events has been measured. We generated the first genome-scale expression compendium of human alternative splicing events using custom whole-transcript microarrays monitoring expression of 24,426 mutually exclusive alternative splicing event pairs in 48 diverse human samples. Over 11,700 genes and 9,500 splicing events were differentially expressed, providing a rich resource for studying splicing regulation. An unbiased, systematic screen of 21,760 4-mer to 7-mer words for cis-regulatory motifs identified 143 RNA 'words' enriched near regulated cassette exons, including six clusters of motifs represented by UCUCU, UGCAUG, UGCU, UGUGU, UUUU, and AGGG, which map to trans-acting regulators PTB, Fox, Muscleblind, CELF/CUG-BP, TIA-1, and hnRNP F/H, respectively. Each cluster showed a distinct pattern of genomic location and tissue specificity. For example, UCUCU occurs 110 to 35 nucleotides preceding cassette exons upregulated in brain and striated muscle but depleted in other tissues. UCUCU and UGCAUG appear to have similar function but independent action, occurring 5' and 3', respectively, of 33% of the cassette exons upregulated in skeletal muscle but co-occurring for only 2%. Keywords: multiple tissue comparison PolyA+ purified RNA pooled from multiple donors of a single human tissue type (e.g. cerebellum) were amplified with random primers and hybridized on a two-color ink-jet oligonucletodie microarray (17 array set) against a common reference pool, comprising ~20 normal adult tissue pools, on custom microarray patterns containing probes to monitor every exon and exon-exon junction in transcript databases, patent databases, and predicted from mouse transcripts. Data were analyzed for gene expression (the average of multiple probes), exon and junction expression, and splice form proportionality (see paper).
Project description:Alternative pre-mRNA splicing is a prevalent mechanism in mammals that promotes proteomic diversity, including expression of cell-type specific protein isoforms. We characterized a role for RBM38 (RNPC1) in regulation of alternative splicing during late erythroid differentiation. We used an affymetrix human exon junction (HJAY) splicing microarray to identify a panel of RBM38-regulated alternatively spliced transcripts. Using microarray databases, we noted high RBM38 expression levels in CD71+ erythroid cells and thus chose to examine RBM38 expression during erythroid differentiation of human hematopoietic stem cells, detecting enhanced RBM38 expression during late erythroid differentiation. In differentiated erythroid cells, we validated a subset of RBM38-regulated splicing events and determined that RBM38 regulates activation of Protein 4.1R (EPB41) exon 16 during late erythroid differentiation. Using Epb41 minigenes, Rbm38 was found to be a robust activator of exon 16 splicing. To further address the mechanism of RBM38-regulated alternative splicing, a novel mammalian protein expression system, followed by SELEX-Seq, was used to identify a GU-rich RBM38 binding motif. Lastly, using a tethering assay, we determined that RBM38 can directly activate splicing when recruited to a downstream intron. Together, our data support the role of RBM38 in regulating alternative splicing during erythroid differentiation.
Project description:RNA-seq was performed on H1299 cells that stably knocking down SRSF1 or control, as well as these cells that were treated with ionizing radiation, in order to profile the alternative splicing events that were regulated by SRSF1 upon ionizing radiation.
Project description:Analysis to identify genome-wide differential alternative splicing events in A549 cells in which the levels of the gene SRSF1 were down-regulated with a specific siRNA