scholarly journals Meta-analysis of small RNA-sequencing errors reveals ubiquitous post-transcriptional RNA modifications

2009 ◽  
Vol 37 (8) ◽  
pp. 2461-2470 ◽  
Author(s):  
H. Alexander Ebhardt ◽  
Herbert H. Tsang ◽  
Denny C. Dai ◽  
Yifeng Liu ◽  
Babak Bostan ◽  
...  
2011 ◽  
Vol 392 (4) ◽  
Author(s):  
Sven Findeiß ◽  
David Langenberger ◽  
Peter F. Stadler ◽  
Steve Hoffmann

Abstract Many aspects of the RNA maturation leave traces in RNA sequencing data in the form of deviations from the reference genomic DNA. This includes, in particular, genomically non-encoded nucleotides and chemical modifications. The latter leave their signatures in the form of mismatches and conspicuous patterns of sequencing reads. Modified mapping procedures focusing on particular types of deviations can help to unravel post-transcriptional modification, maturation and degradation processes. Here, we focus on small RNA sequencing data that is produced in large quantities aimed at the analysis of microRNA expression. Starting from the recovery of many well known modified sites in tRNAs, we provide evidence that modified nucleotides are a pervasive phenomenon in these data sets. Regarding non-encoded nucleotides we concentrate on CCA tails, which surprisingly can be found in a diverse collection of transcripts including sub-populations of mature microRNAs. Although small RNA sequencing libraries alone are insufficient to obtain a complete picture, they can inform on many aspects of the complex processes of RNA maturation.


2021 ◽  
Author(s):  
Jose Francisco Sanchez-Herrero ◽  
Raquel Pluvinet ◽  
Antonio Luna-de Haro ◽  
Lauro Sumoy

Abstract Background Next generation sequencing has allowed the discovery of miRNA isoforms, termed isomirs. Some isomirs are derived from imprecise processing of pre-miRNA precursors, leading to length variants. Additional variability is introduced by non-templated addition of bases at the ends or editing of internal bases, resulting in base differences relative to the template DNA sequence. We hypothesized that some component of the isomir variation reported so far could be due to systematic technical noise and not real. Results We have developed the XICRA pipeline to analyze small RNA sequencing data at the isomir level. We exploited its ability to use single or merged reads to compare isomir results derived from paired-end (PE) reads with those from single reads (SR) to address whether detectable sequence differences relative to canonical miRNAs found in isomirs are true biological variations or the result of errors in sequencing. We have detected non-negligible systematic differences between SR and PE data which primarily affect putative internally edited isomirs, and at a much smaller frequency terminal length changing isomirs. This is relevant for the identification of true isomirs in small RNA sequencing datasets. Conclusions We conclude that potential artifacts derived from sequencing errors and/or data processing could result in an overestimation of abundance and diversity of miRNA isoforms. Efforts in annotating the isomirnome should take this into account.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Jose Francisco Sanchez Herrero ◽  
Raquel Pluvinet ◽  
Antonio Luna de Haro ◽  
Lauro Sumoy

Abstract Background Next generation sequencing has allowed the discovery of miRNA isoforms, termed isomiRs. Some isomiRs are derived from imprecise processing of pre-miRNA precursors, leading to length variants. Additional variability is introduced by non-templated addition of bases at the ends or editing of internal bases, resulting in base differences relative to the template DNA sequence. We hypothesized that some component of the isomiR variation reported so far could be due to systematic technical noise and not real. Results We have developed the XICRA pipeline to analyze small RNA sequencing data at the isomiR level. We exploited its ability to use single or merged reads to compare isomiR results derived from paired-end (PE) reads with those from single reads (SR) to address whether detectable sequence differences relative to canonical miRNAs found in isomiRs are true biological variations or the result of errors in sequencing. We have detected non-negligible systematic differences between SR and PE data which primarily affect putative internally edited isomiRs, and at a much smaller frequency terminal length changing isomiRs. This is relevant for the identification of true isomiRs in small RNA sequencing datasets. Conclusions We conclude that potential artifacts derived from sequencing errors and/or data processing could result in an overestimation of abundance and diversity of miRNA isoforms. Efforts in annotating the isomiRnome should take this into account.


2020 ◽  
pp. 109158182096151
Author(s):  
Jennifer C. Shing ◽  
Kai Schaefer ◽  
Shaun E. Grosskurth ◽  
Andy H. Vo ◽  
Tatiana Sharapova ◽  
...  

Predictive indicators of testicular toxicity could improve drug development by allowing early in-life screening for this adverse effect before it becomes severe. We hypothesized that circulating microRNAs (miRNAs) could serve as testicular toxicity biomarkers in dogs. Herein, we describe the results of an exploratory study conducted to discover biomarkers of drug-induced testicular injury. Following a dose-selection study using the testicular toxicant ethylene glycol monomethyl ether (EGME), we chose a dose of 50 mg/kg/d EGME to avoid systemic toxicity and treated 2 groups of dogs (castrated, non-castrated) for 14 to 28 days. Castrated animals were used as negative controls to identify biomarkers specific for testicular toxicity because EGME can cause toxicity to organ systems in addition to the testis. Blood was collected daily during the dosing period, followed by recovery for 29 to 43 days with less frequent sampling. Dosing was well tolerated, resulting in mild-to-moderate degeneration in testes and epididymides. Global profiling of serum miRNAs at selected dosing and recovery time points was completed by small RNA sequencing. Bioinformatics data analysis using linear modeling demonstrated several circulating miRNAs that were differentially abundant during the dosing period compared with baseline and/or castrated control samples. Confirmatory reverse transcription quantitative polymerase chain reaction data in these animals was unable to detect sustained alterations of miRNAs in serum, except for 1 potential candidate cfa-miR-146b. Taken together, we report the results of a comprehensive exploratory study and suggest future directions for follow-up research to address the challenge of developing diagnostic biomarkers of testicular toxicity.


Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 964
Author(s):  
Sarka Benesova ◽  
Mikael Kubista ◽  
Lukas Valihrach

MicroRNAs (miRNAs) are a class of small RNA molecules that have an important regulatory role in multiple physiological and pathological processes. Their disease-specific profiles and presence in biofluids are properties that enable miRNAs to be employed as non-invasive biomarkers. In the past decades, several methods have been developed for miRNA analysis, including small RNA sequencing (RNA-seq). Small RNA-seq enables genome-wide profiling and analysis of known, as well as novel, miRNA variants. Moreover, its high sensitivity allows for profiling of low input samples such as liquid biopsies, which have now found applications in diagnostics and prognostics. Still, due to technical bias and the limited ability to capture the true miRNA representation, its potential remains unfulfilled. The introduction of many new small RNA-seq approaches that tried to minimize this bias, has led to the existence of the many small RNA-seq protocols seen today. Here, we review all current approaches to cDNA library construction used during the small RNA-seq workflow, with particular focus on their implementation in commercially available protocols. We provide an overview of each protocol and discuss their applicability. We also review recent benchmarking studies comparing each protocol’s performance and summarize the major conclusions that can be gathered from their usage. The result documents variable performance of the protocols and highlights their different applications in miRNA research. Taken together, our review provides a comprehensive overview of all the current small RNA-seq approaches, summarizes their strengths and weaknesses, and provides guidelines for their applications in miRNA research.


2013 ◽  
Vol 12 (11) ◽  
pp. 2036-2044 ◽  
Author(s):  
Dong-qing SHI ◽  
Yuan ZHANG ◽  
Jin-hu MA ◽  
Yu-long LI ◽  
Jin XU

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Kasey C Vickers ◽  
Michael G Levin ◽  
Michael P Anderson ◽  
Qing Xu ◽  
Joshua Anzinger ◽  
...  

Many HDL-microRNAs (miRNA) are well-characterized post-transcriptional regulators of inflammation, and are significantly increased on HDL with hypercholesterolemia and atherosclerosis in humans and mice. Therefore, we hypothesize that inflammatory cells uniquely control their own gene expression through cellular miRNA export to HDL and then regulate recipient cell gene expression through HDL-mediated miRNA delivery. To test this hypothesis, we used high-throughput proteomics, Open Arrays, small RNA sequencing, and gene expression microarrays. Human monocytes (plasma elutriation) were differentiated into dendritic cells and multiple macrophage phenotypes. Each cell-type was incubated with pure reconstituted HDL (rHDL), which was then purified from culture media by apolipoprotein A-I immunoprecipitation after 24 h, and both cellular and HDL-miRNAs were profiled using TaqMan Open Arrays. Macrophages were found to export high levels of miRNAs to HDL that inhibit monocyte/macrophage differentiation (miR-146a, miR-223); however, monocytes were also found to export many miRNAs associated with differentiation, including miR-92a, miR-222, miR-17, miR-20a, miR106a, and miR-21. Furthermore, many miRNAs were found to be transcribed in inflammatory cells, but completely exported to HDL and not retained in the cell. Most interestingly, HDL treatment was found to induce miR-223 transcription in monocytes, as determined by primary miR-223 transcript levels; however, intracellular levels of the mature form (miR-223) did not change. These results suggest that HDL induces the export of miRNAs it transports. PAR-CLIP with high-throughput small RNA sequencing was used to demonstrate that miRNAs are transferred from macrophages to endothelial cells and loaded onto cellular Argonaute 2-continaining RNA-induced silencing complexes. To demonstrate this in mice, human HDL, containing endogenous levels of miR-223, were injected into miR-223-null mice and inflammation-associated miRNA delivery was mapped in vivo. In summary, we found profound differences in the cellular response to HDL treatment and HDL-miRNA communication amongst inflammatory cell phenotypes that are physiologically relevant to cardiovascular disease.


2018 ◽  
Vol 58 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Priyanka Kanth ◽  
Mark W. Hazel ◽  
Kenneth M. Boucher ◽  
Zhihong Yang ◽  
Li Wang ◽  
...  

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