Modeling Alternative Splicing Variants from RNA-Seq Data with Isoform Graphs

Abstract Aberrant alternative splicing (AS) events serve as prognostic indicators in a large number of malignancies, whereas comprehensive analysis of prognostic AS in gastric cancer (GC) has not yet been understood. To identify prognostic AS events and clarify the function of the splicing variants in GC. RNA-Seq data, clinical information and percent spliced in (PSI) values were available in the cancer genome atlas (TCGA) and TCGA SpliceSeq data portal. A three-step regression method was conducted to screen prognostic AS events and construct multi-AS-based signatures. The associations between prognostic AS events and splicing factors were also investigated. We identified a total of 1318 survival related AS events in GC, Parent genes of which were implicated in numerous oncogenic pathways. The final prognostic signatures stratified by seven types of AS events or not stratified performed well in risk prediction for GC patients. Moreover, five signatures base on AA, AD, AT, ES and RI events function as independent prognostic indicators after multivariate adjustment of clinicalpathological variables. Splicing network also showed marked correlation between the expression of splicing factors and PSI value of AS events in GC patients. The AS derived signatures allow to predict GC prognosis and might serve as potential therapeutic target for GC.

Download Full-text

Comparative Transcriptome Analysis Reveals Sex-Based Differences during the Development of the Adult Parasitic Wasp Cotesia vestalis (Hymenoptera: Braconidae)

Genes ◽

10.3390/genes12060896 ◽

2021 ◽

Vol 12 (6) ◽

pp. 896

Author(s):

Yuenan Zhou ◽

Pei Yang ◽

Shuang Xie ◽

Min Shi ◽

Jianhua Huang ◽

...

Keyword(s):

Alternative Splicing ◽

Adult Development ◽

Sexual Development ◽

Molecular Mechanisms ◽

Parasitic Wasp ◽

Differentially Expressed Gene ◽

Regulation Mechanism ◽

Rna Seq ◽

Male And Female ◽

Cotesia Vestalis

The endoparasitic wasp Cotesia vestalis is an important biological agent for controlling the population of Plutella xylostella, a major pest of cruciferous crops worldwide. Though the genome of C. vestalis has recently been reported, molecular mechanisms associated with sexual development have not been comprehensively studied. Here, we combined PacBio Iso-Seq and Illumina RNA-Seq to perform genome-wide profiling of pharate adult and adult development of male and female C. vestalis. Taking advantage of Iso-Seq full-length reads, we identified 14,466 novel transcripts as well as 8770 lncRNAs, with many lncRNAs showing a sex- and stage-specific expression pattern. The differentially expressed gene (DEG) analyses showed 2125 stage-specific and 326 sex-specific expressed genes. We also found that 4819 genes showed 11,856 alternative splicing events through combining the Iso-Seq and RNA-Seq data. The results of comparative analyses showed that most genes were alternatively spliced across developmental stages, and alternative splicing (AS) events were more prevalent in females than in males. Furthermore, we identified six sex-determining genes in this parasitic wasp and verified their sex-specific alternative splicing profiles. Specifically, the characterization of feminizer and doublesex splicing between male and female implies a conserved regulation mechanism of sexual development in parasitic wasps.

Download Full-text

Characterization of alternative splicing events and prognostic signatures in breast cancer

BMC Cancer ◽

10.1186/s12885-021-08305-6 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Pihua Han ◽

Jingjun Zhu ◽

Guang Feng ◽

Zizhang Wang ◽

Yanni Ding

Keyword(s):

Breast Cancer ◽

Alternative Splicing ◽

Proportional Hazards ◽

Pearson Correlation ◽

Original Data ◽

Cox Proportional Hazards ◽

Prognostic Indicators ◽

Splicing Factors ◽

Rna Seq

Abstract Background Breast cancer (BRCA) is one of the most common cancers worldwide. Abnormal alternative splicing (AS) frequently observed in cancers. This study aims to demonstrate AS events and signatures that might serve as prognostic indicators for BRCA. Methods Original data for all seven types of splice events were obtained from TCGA SpliceSeq database. RNA-seq and clinical data of BRCA cohorts were downloaded from TCGA database. Survival-associated AS events in BRCA were analyzed by univariate COX proportional hazards regression model. Prognostic signatures were constructed for prognosis prediction in patients with BRCA based on survival-associated AS events. Pearson correlation analysis was performed to measure the correlation between the expression of splicing factors (SFs) and the percent spliced in (PSI) values of AS events. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were conducted to demonstrate pathways in which survival-associated AS event is enriched. Results A total of 45,421 AS events in 21,232 genes were identified. Among them, 1121 AS events in 931 genes significantly correlated with survival for BRCA. The established AS prognostic signatures of seven types could accurately predict BRCA prognosis. The comprehensive AS signature could serve as independent prognostic factor for BRCA. A SF-AS regulatory network was therefore established based on the correlation between the expression levels of SFs and PSI values of AS events. Conclusions This study revealed survival-associated AS events and signatures that may help predict the survival outcomes of patients with BRCA. Additionally, the constructed SF-AS networks in BRCA can reveal the underlying regulatory mechanisms in BRCA.

Download Full-text

GLiMMPS: Robust statistical model for regulatory variation of alternative splicing using RNA-seq data

Genome Biology ◽

10.1186/gb-2013-14-7-r74 ◽

2013 ◽

Vol 14 (7) ◽

pp. R74 ◽

Cited By ~ 56

Author(s):

Keyan Zhao ◽

Zhi-xiang Lu ◽

Juw Park ◽

Qing Zhou ◽

Yi Xing

Keyword(s):

Alternative Splicing ◽

Statistical Model ◽

Rna Seq ◽

Regulatory Variation

Download Full-text

Alternative splicing variants of carbonic anhydrase IX in human non-small cell lung cancer

Lung Cancer ◽

10.1016/j.lungcan.2008.10.001 ◽

2009 ◽

Vol 64 (3) ◽

pp. 271-276 ◽

Cited By ~ 21

Author(s):

Francesca Malentacchi ◽

Lisa Simi ◽

Caterina Nannelli ◽

Matteo Andreani ◽

Alberto Janni ◽

...

Keyword(s):

Lung Cancer ◽

Alternative Splicing ◽

Carbonic Anhydrase ◽

Small Cell Lung Cancer ◽

Cell Lung Cancer ◽

Small Cell ◽

Carbonic Anhydrase Ix ◽

Small Cell Lung ◽

Splicing Variants

Download Full-text

Plant buffering against the high-light stress-induced accumulation of CsGA2ox8 transcripts via alternative splicing to finely tune gibberellin levels and maintain hypocotyl elongation

Horticulture Research ◽

10.1038/s41438-020-00430-w ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Bin Liu ◽

Shuo Zhao ◽

Pengli Li ◽

Yilu Yin ◽

Qingliang Niu ◽

...

Keyword(s):

Alternative Splicing ◽

Light Intensity ◽

Intron Retention ◽

Light Stress ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Rna Seq ◽

Multiple Transcripts ◽

Novel Transcript

AbstractIn plants, alternative splicing (AS) is markedly induced in response to environmental stresses, but it is unclear why plants generate multiple transcripts under stress conditions. In this study, RNA-seq was performed to identify AS events in cucumber seedlings grown under different light intensities. We identified a novel transcript of the gibberellin (GA)-deactivating enzyme Gibberellin 2-beta-dioxygenase 8 (CsGA2ox8). Compared with canonical CsGA2ox8.1, the CsGA2ox8.2 isoform presented intron retention between the second and third exons. Functional analysis proved that the transcript of CsGA2ox8.1 but not CsGA2ox8.2 played a role in the deactivation of bioactive GAs. Moreover, expression analysis demonstrated that both transcripts were upregulated by increased light intensity, but the expression level of CsGA2ox8.1 increased slowly when the light intensity was >400 µmol·m−2·s−1 PPFD (photosynthetic photon flux density), while the CsGA2ox8.2 transcript levels increased rapidly when the light intensity was >200 µmol·m−2·s−1 PPFD. Our findings provide evidence that plants might finely tune their GA levels by buffering against the normal transcripts of CsGA2ox8 through AS.

Download Full-text

Detection of alternative splicing in Diabrotica virgifera virgifera LeConte, in association with Bt resistance using RNA-seq and PacBio Iso-Seq

10.1101/2020.08.03.234682 ◽

2020 ◽

Author(s):

Zixiao Zhao ◽

Christine G. Elsik ◽

Bruce E. Hibbard ◽

Kent S. Shelby

Keyword(s):

Alternative Splicing ◽

Matrix Protein ◽

Diabrotica Virgifera Virgifera ◽

Western Corn Rootworm ◽

Corn Rootworm ◽

Diabrotica Virgifera ◽

Rna Seq ◽

Bt Resistance ◽

Bt Toxins ◽

Alternatively Spliced

AbstractBackgroundAlternative splicing is one of the major mechanisms that increases transcriptome diversity in eukaryotes, including insect species that have gained resistance to pesticides and Bt toxins. In western corn rootworm (Diabrotica virgifera virgifera LeConte), neither alternative splicing nor its role in resistance to Bt toxins has been studied.ResultsTo investigate the mechanisms of Bt resistance we carried out single-molecule real-time (SMRT) transcript sequencing and Iso-seq analysis on resistant, eCry3.1Ab-selected and susceptible, unselected, western corn rootworm neonate midguts which fed on seedling maize with and without eCry3.1Ab for 12 and 24 hours. We present transcriptome-wide alternative splicing patterns of western corn rootworm midgut in response to feeding on eCry3.1Ab-expressing corn using a comprehensive approach that combines both RNA-seq and SMRT transcript sequencing techniques. We found that 67.73% of multi-exon genes are alternatively spliced, which is consistent with the high transposable element content of the genome. One of the alternative splicing events we identified was a novel peritrophic matrix protein with two alternative splicing isoforms. Analysis of differential exon usage between resistant and susceptible colonies showed that in eCry3.1Ab-resistant western corn rootworm, expression of one isoform was significantly higher than in the susceptible colony, while no significant differences between colonies were observed with the other isoform.ConclusionOur results provide the first survey of alternative splicing in western corn rootworm and suggest that the observed alternatively spliced isoforms of peritrophic matrix protein may be associated with eCry3.1Ab resistance in western corn rootworm.

Download Full-text

Exploration of Alternative Splicing (AS) Events in MDV-Infected Chicken Spleens

Genes ◽

10.3390/genes12121857 ◽

2021 ◽

Vol 12 (12) ◽

pp. 1857

Author(s):

Lulu Wang ◽

Gang Zheng ◽

Yiming Yuan ◽

Ziyi Wang ◽

Changjun Liu ◽

...

Keyword(s):

Alternative Splicing ◽

Infection Process ◽

Marek's Disease ◽

Individual Development ◽

Control Group ◽

P Value ◽

Marek’S Disease ◽

Rna Seq ◽

Infected Chicken ◽

Structural Variations

Marek’s disease (MD) was an immunosuppression disease induced by Marek’s disease virus (MDV). MD caused huge economic loss to the global poultry industry, but it also provided an ideal model for studying diseases induced by the oncogenic virus. Alternative splicing (AS) simultaneously produced different isoform transcripts, which are involved in various diseases and individual development. To investigate AS events in MD, RNA-Seq was performed in tumorous spleens (TS), spleens from the survivors (SS) without any lesion after MDV infection, and non-infected chicken spleens (NS). In this study, 32,703 and 25,217 AS events were identified in TS and SS groups with NS group as the control group, and 1198, 1204, and 348 differently expressed (DE) AS events (p-value < 0.05 and FDR < 0.05) were identified in TS vs. NS, TS vs. SS, SS vs. NS, respectively. Additionally, Function enrichment analysis showed that ubiquitin-mediated proteolysis, p53 signaling pathway, and phosphatidylinositol signaling system were significantly enriched (p-value < 0.05). Small structural variations including SNP and indel were analyzed based on RNA-Seq data, and it showed that the TS group possessed more variants on the splice site region than those in SS and NS groups, which might cause more AS events in the TS group. Combined with previous circRNA data, we found that 287 genes could produce both circular and linear RNAs, which suggested these genes were more active in MD lymphoma transformation. This study has expanded the understanding of the MDV infection process and provided new insights for further analysis of resistance/susceptibility mechanisms.

Download Full-text

Estimation of alternative splicing isoform frequencies from RNA-Seq data

Algorithms for Molecular Biology ◽

10.1186/1748-7188-6-9 ◽

2011 ◽

Vol 6 (1) ◽

Cited By ~ 115

Author(s):

Marius Nicolae ◽

Serghei Mangul ◽

Ion I Măndoiu ◽

Alex Zelikovsky

Keyword(s):

Alternative Splicing ◽

Rna Seq

Download Full-text