Project description:Circular RNA (circRNA) is a group of RNA family generated by RNA circularization, which was discovered ubiquitously across different cancers. However, the internal structure of circRNA is hard to be determined since of the alternative splicing happened in exons and introns of circRNA and the cancer-specific alternative splicing of circRNA is less to be identified. Here we proposed a custom tool CircSplice, which could identify internal alternative splicing of circRNA and compare the differential splicing between samples. By applying CircSplice in ccRCC, we identified cancer-specific alternative splicing (AS) events belong to circRNAs in ccRCC. We further confirmed the existence of alternative splicing events in circRNAs by RT-PCR. This study is the first exploration of cancer-specific alternative splicing in circRNAs, which helps researchers to better understand potential functions of splicing of circRNAs in cancers.
Project description:Circular RNA (circRNA) is a group of RNA families generated by RNA circularization, which was discovered ubiquitously across different cancers. However, the internal structure of circRNA is difficult to determine due to alternative splicing that occurs in its exons and introns. Furthermore, cancer-specific alternative splicing of circRNA is less likely to be identified. Here, we proposed a de novo algorithm, CircSplice, that could identify internal alternative splicing in circRNA and compare differential circRNA splicing events between different conditions ( http://gb.whu.edu.cn/CircSplice or https://github.com/GeneFeng/CircSplice ). By applying CircSplice in clear cell renal cell carcinoma and bladder cancer, we detected 4498 and 2977 circRNA alternative splicing (circ-AS) events in the two datasets respectively and confirmed the expression of circ-AS events by RT-PCR. We further inspected the distributions and patterns of circ-AS in cancer and adjacent normal tissues. To further understand the potential functions of cancer-specific circ-AS, we classified those events into tumor suppressors and oncogenes and performed pathway enrichment analysis. This study is the first comprehensive view of cancer-specific circRNA alternative splicing, which could contribute significantly to regulation and functional research of circRNAs in cancers.
Project description:This SuperSeries is composed of the following subset Series: GSE23513: Position-dependent alternative splicing activity revealed by global profiling of alternative splicing events regulated by PTB (HJAY) GSE23514: Position-dependent alternative splicing activity revealed by global profiling of alternative splicing events regulated by PTB (Exon array) Refer to individual Series
Project description:Alternative splicing (AS) plays a crucial role in the diversification of gene function and regulation. Consequently, the systematic identification and characterization of temporally regulated splice variants is of critical importance to understanding animal development. We have used high-throughput RNA sequencing and microarray profiling to analyze AS in C. elegans across various stages of development. This analysis identified thousands of novel splicing events, including hundreds of developmentally regulated AS events. To make these data easily accessible and informative, we constructed the C. elegans Splice Browser, a web resource in which researchers can mine AS events of interest and retrieve information about their relative levels and regulation across development. The data presented in this study, along with the Splice Browser, provides the most comprehensive set of annotated splice variants in C. elegans to date, and is therefore expected to faciliate focused, high resolution in vivo functional assays of AS function. Alternative splicing events were identified from alignments of C. elegans mRNA/EST sequences (UniGene Build #26) to C. elegans genomic sequence (NCBI timestamp: Sept. 25, 2006), essentially as previously described (Pan et al. 2005; Pan et al. 2004). In total, 499 cassette type AS events were identified. For each AS event, 3 exon probes and 3 exon junction probes were designed to profile the AS event on the microarray, essentially as previously described (Pan et al. 2004). This submission represents the expression microarray component of the study.
Project description:Alternative polyadenylation has been implicated as an important regulator of gene expression. In some cases, alternative polyadenylation is known to couple with alternative splicing to influence last intron removal. However, it is unknown whether alternative polyadenylation events influence alternative splicing decisions at upstream exons. Knockdown of the polyadenylation factors CFIm25 or CstF64 was used as an approach in identifying alternative polyadenylation and alternative splicing events on a genome-wide scale. Although hundreds of alternative splicing events were found to be differentially spliced in the knockdown of CstF64, genes associated with alternative polyadenylation did not exhibit an increased incidence of alternative splicing. These results demonstrate that the coupling between alternative polyadenylation and alternative splicing is usually limited to defining the last exon. The striking influence of CstF64 knockdown on alternative splicing can be explained through its effects on UTR selection of known splicing regulators such as hnRNP A2/B1, thereby indirectly influencing splice site selection. We conclude that changes in the expression of the polyadenylation factor CstF64 influences alternative splicing through indirect effects. HeLa cell line was stably transfected with shRNA plasmids targeting CstF64. Total RNA was isolated from CstF64 KD cells and wild-type control cells using Trizol according to manufacturerâs protocols. Samples were deep sequenced in duplicate using the Illumina GAIIx system.