scholarly journals spliceR: An R package for classification of alternative splicing and prediction of coding potential from RNA-seq data

Author(s):  
Kristoffer Vitting-Seerup ◽  
Bo T Porse ◽  
Albin Sandelin ◽  
Johannes E Waage

Background: With the increasing depth and decreasing costs of RNA-sequencing researchers are now able to profile the transcriptome with unprecedented detail. These advances not only allow for precise approximation of gene expression levels, but also for the characterization of alternative transcript usage/switching between conditions. Recent software improvements in full-length transcript deconvolution prompted us to develop spliceR, an R package for classification of alternative splicing and prediction of coding potential. Results: spliceR uses the full-length transcripts output from RNA-seq assemblers, to detect single- and multiple exon skipping, alternative donor and acceptor sites, intron retention, alternative first or last exon usage, and mutually exclusive exon events. For each of these events spliceR also annotates the genomic coordinates of the differentially spliced elements facilitating downstream sequence analysis. Furthermore, isoform fraction values are calculated for effective post-filtering, i.e. identification of transcript switching between conditions. Lastly spliceR predicts the coding potential, as well as the potential nonsense mediated decay (NMD) sensitivity of each transcript. Conclusions: spliceR is a easy-to-use tool that allows detection of alternative splicing, transcript switching and NMD sensitivity from RNA-seq data, extending the usability of RNA-seq and assembly technologies. spliceR is implemented as an R package and is freely available from the Bioconductor repository (http://www.bioconductor.org/packages/2.13/bioc/html/spliceR.html).

2013 ◽  
Author(s):  
Kristoffer Vitting-Seerup ◽  
Bo T Porse ◽  
Albin Sandelin ◽  
Johannes E Waage

Background: With the increasing depth and decreasing costs of RNA-sequencing researchers are now able to profile the transcriptome with unprecedented detail. These advances not only allow for precise approximation of gene expression levels, but also for the characterization of alternative transcript usage/switching between conditions. Recent software improvements in full-length transcript deconvolution prompted us to develop spliceR, an R package for classification of alternative splicing and prediction of coding potential. Results: spliceR uses the full-length transcripts output from RNA-seq assemblers, to detect single- and multiple exon skipping, alternative donor and acceptor sites, intron retention, alternative first or last exon usage, and mutually exclusive exon events. For each of these events spliceR also annotates the genomic coordinates of the differentially spliced elements facilitating downstream sequence analysis. Furthermore, isoform fraction values are calculated for effective post-filtering, i.e. identification of transcript switching between conditions. Lastly spliceR predicts the coding potential, as well as the potential nonsense mediated decay (NMD) sensitivity of each transcript. Conclusions: spliceR is a easy-to-use tool that allows detection of alternative splicing, transcript switching and NMD sensitivity from RNA-seq data, extending the usability of RNA-seq and assembly technologies. spliceR is implemented as an R package and is freely available from the Bioconductor repository (http://www.bioconductor.org/packages/2.13/bioc/html/spliceR.html).


2013 ◽  
Author(s):  
Kristoffer Vitting-Seerup ◽  
Bo T Porse ◽  
Albin Sandelin ◽  
Johannes E Waage

With the advent of increasing depth and decreasing costs in digital gene expression technologies exemplified by RNA-sequencing, researchers are now able to profile the transcriptome with unprecedented detail. These advances not only allow for precise approximation of gene expression levels, but also for characterization of alternative isoform usage/switching between samples. Recent software improvements in full transcript deconvolution prompted us to develop spliceR , an R package for classification of alternative splicing. spliceR labels isoforms based on fully assembled transcripts, detecting single- and multiple exon skipping, alternative donor or acceptor sites, intron retention, alternative first or last exon usage, and mutually exclusive exon events. Alongside, event spliced-in/out values are calculated for effective post-filtering, and genomic coordinates of differentially spliced elements are annotated for downstream sequence analysis. Furthermore, spliceR has the option to predict the coding potential and thereby the nonsense mediated decay (NMD) sensitivity of transcripts based on stop codon position.


2014 ◽  
Vol 15 (1) ◽  
pp. 81 ◽  
Author(s):  
Kristoffer Vitting-Seerup ◽  
Bo Porse ◽  
Albin Sandelin ◽  
Johannes Waage

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Guiomar Martín ◽  
Yamile Márquez ◽  
Federica Mantica ◽  
Paula Duque ◽  
Manuel Irimia

Abstract Background Alternative splicing (AS) is a widespread regulatory mechanism in multicellular organisms. Numerous transcriptomic and single-gene studies in plants have investigated AS in response to specific conditions, especially environmental stress, unveiling substantial amounts of intron retention that modulate gene expression. However, a comprehensive study contrasting stress-response and tissue-specific AS patterns and directly comparing them with those of animal models is still missing. Results We generate a massive resource for Arabidopsis thaliana, PastDB, comprising AS and gene expression quantifications across tissues, development and environmental conditions, including abiotic and biotic stresses. Harmonized analysis of these datasets reveals that A. thaliana shows high levels of AS, similar to fruitflies, and that, compared to animals, disproportionately uses AS for stress responses. We identify core sets of genes regulated specifically by either AS or transcription upon stresses or among tissues, a regulatory specialization that is tightly mirrored by the genomic features of these genes. Unexpectedly, non-intron retention events, including exon skipping, are overrepresented across regulated AS sets in A. thaliana, being also largely involved in modulating gene expression through NMD and uORF inclusion. Conclusions Non-intron retention events have likely been functionally underrated in plants. AS constitutes a distinct regulatory layer controlling gene expression upon internal and external stimuli whose target genes and master regulators are hardwired at the genomic level to specifically undergo post-transcriptional regulation. Given the higher relevance of AS in the response to different stresses when compared to animals, this molecular hardwiring is likely required for a proper environmental response in A. thaliana.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Bin Liu ◽  
Shuo Zhao ◽  
Pengli Li ◽  
Yilu Yin ◽  
Qingliang Niu ◽  
...  

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.


DNA Research ◽  
2019 ◽  
Vol 26 (4) ◽  
pp. 301-311 ◽  
Author(s):  
Yue Zhang ◽  
Tonny Maraga Nyong'A ◽  
Tao Shi ◽  
Pingfang Yang

Abstract Alternative splicing (AS) plays a critical role in regulating different physiological and developmental processes in eukaryotes, by dramatically increasing the diversity of the transcriptome and the proteome. However, the saturation and complexity of AS remain unclear in lotus due to its limitation of rare obtainment of full-length multiple-splice isoforms. In this study, we apply a hybrid assembly strategy by combining single-molecule real-time sequencing and Illumina RNA-seq to get a comprehensive insight into the lotus transcriptomic landscape. We identified 211,802 high-quality full-length non-chimeric reads, with 192,690 non-redundant isoforms, and updated the lotus reference gene model. Moreover, our analysis identified a total of 104,288 AS events from 16,543 genes, with alternative 3ʹ splice-site being the predominant model, following by intron retention. By exploring tissue datasets, 370 tissue-specific AS events were identified among 12 tissues. Both the tissue-specific genes and isoforms might play important roles in tissue or organ development, and are suitable for ‘ABCE’ model partly in floral tissues. A large number of AS events and isoform variants identified in our study enhance the understanding of transcriptional diversity in lotus, and provide valuable resource for further functional genomic studies.


2020 ◽  
Vol 10 (10) ◽  
pp. 3797-3810
Author(s):  
Manishi Pandey ◽  
Gary D. Stormo ◽  
Susan K. Dutcher

Genome-wide analysis of transcriptome data in Chlamydomonas reinhardtii shows periodic patterns in gene expression levels when cultures are grown under alternating light and dark cycles so that G1 of the cell cycle occurs in the light phase and S/M/G0 occurs during the dark phase. However, alternative splicing, a process that enables a greater protein diversity from a limited set of genes, remains largely unexplored by previous transcriptome based studies in C. reinhardtii. In this study, we used existing longitudinal RNA-seq data obtained during the light-dark cycle to investigate the changes in the alternative splicing pattern and found that 3277 genes (19.75% of 17,746 genes) undergo alternative splicing. These splicing events include Alternative 5′ (Alt 5′), Alternative 3′ (Alt 3′) and Exon skipping (ES) events that are referred as alternative site selection (ASS) events and Intron retention (IR) events. By clustering analysis, we identified a subset of events (26 ASS events and 10 IR events) that show periodic changes in the splicing pattern during the cell cycle. About two-thirds of these 36 genes either introduce a pre-termination codon (PTC) or introduce insertions or deletions into functional domains of the proteins, which implicate splicing in altering gene function. These findings suggest that alternative splicing is also regulated during the Chlamydomonas cell cycle, although not as extensively as changes in gene expression. The longitudinal changes in the alternative splicing pattern during the cell cycle captured by this study provides an important resource to investigate alternative splicing in genes of interest during the cell cycle in Chlamydomonas reinhardtii and other eukaryotes.


Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 820 ◽  
Author(s):  
Chao Zeng ◽  
Michiaki Hamada

Alternative splicing, a ubiquitous phenomenon in eukaryotes, is a regulatory mechanism for the biological diversity of individual genes. Most studies have focused on the effects of alternative splicing for protein synthesis. However, the transcriptome-wide influence of alternative splicing on RNA subcellular localization has rarely been studied. By analyzing RNA-seq data obtained from subcellular fractions across 13 human cell lines, we identified 8720 switching genes between the cytoplasm and the nucleus. Consistent with previous reports, intron retention was observed to be enriched in the nuclear transcript variants. Interestingly, we found that short and structurally stable introns were positively correlated with nuclear localization. Motif analysis reveals that fourteen RNA-binding protein (RBPs) are prone to be preferentially bound with such introns. To our knowledge, this is the first transcriptome-wide study to analyze and evaluate the effect of alternative splicing on RNA subcellular localization. Our findings reveal that alternative splicing plays a promising role in regulating RNA subcellular localization.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Anne-Laure Bougé ◽  
Eva Murauer ◽  
Emmanuelle Beyne ◽  
Julie Miro ◽  
Jessica Varilh ◽  
...  

Abstract We have analysed the splicing pattern of the human Duchenne Muscular Dystrophy (DMD) transcript in normal skeletal muscle. To achieve depth of coverage required for the analysis of this lowly expressed gene in muscle, we designed a targeted RNA-Seq procedure that combines amplification of the full-length 11.3 kb DMD cDNA sequence and 454 sequencing technology. A high and uniform coverage of the cDNA sequence was obtained that allowed to draw up a reliable inventory of the physiological alternative splicing events in the muscular DMD transcript. In contrast to previous assumptions, we evidenced that most of the 79 DMD exons are constitutively spliced in skeletal muscle. Only a limited number of 12 alternative splicing events were identified, all present at a very low level. These include previously known exon skipping events but also newly described pseudoexon inclusions and alternative 3′ splice sites, of which one is the first functional NAGNAG splice site reported in the DMD gene. This study provides the first RNA-Seq-based reference of DMD splicing pattern in skeletal muscle and reports on an experimental procedure well suited to detect condition-specific differences in this low abundance transcript that may prove useful for diagnostic, research or RNA-based therapeutic applications.


2015 ◽  
Vol 28 (3) ◽  
pp. 298-309 ◽  
Author(s):  
Alyssa Burkhardt ◽  
Alex Buchanan ◽  
Jason S. Cumbie ◽  
Elizabeth A. Savory ◽  
Jeff H. Chang ◽  
...  

Pseudoperonospora cubensis is an obligate pathogen and causative agent of cucurbit downy mildew. To help advance our understanding of the pathogenicity of P. cubensis, we used RNA-Seq to improve the quality of its reference genome sequence. We also characterized the RNA-Seq dataset to inventory transcript isoforms and infer alternative splicing during different stages of its development. Almost half of the original gene annotations were improved and nearly 4,000 previously unannotated genes were identified. We also demonstrated that approximately 24% of the expressed genome and nearly 55% of the intron-containing genes from P. cubensis had evidence for alternative splicing. Our analyses revealed that intron retention is the predominant alternative splicing type in P. cubensis, with alternative 5′- and alternative 3′-splice sites occurring at lower frequencies. Representatives of the newly identified genes and predicted alternatively spliced transcripts were experimentally validated. The results presented herein highlight the utility of RNA-Seq for improving draft genome annotations and, through this approach, we demonstrate that alternative splicing occurs more frequently than previously predicted. In total, the current study provides evidence that alternative splicing plays a key role in transcriptome regulation and proteome diversification in plant-pathogenic oomycetes.


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