scholarly journals Excess primer degradation by Exo I improves the preparation of 3′ cDNA ligation-based sequencing libraries

BioTechniques ◽  
2019 ◽  
Vol 67 (3) ◽  
pp. 110-116
Author(s):  
Christel Hougård Enroth ◽  
Annaleigh Ohrt Fehler ◽  
Line Dahl Poulsen ◽  
Jeppe Vinther
Keyword(s):  
Escherichia Coli ◽  
Rna Sequencing ◽  
Small Rna ◽  
Reverse Transcription ◽  
Library Construction ◽  
Reverse Transcription Primer ◽  
Adapter Ligation ◽  
Sequencing Library

RNA sequencing library construction using single-stranded ligation of a DNA adapter to 3′ ends of cDNAs often produces primer–adapter byproducts, which compete with cDNA–adapter ligation products during library amplification and, therefore, reduces the number of informative sequencing reads. We find that Escherichia coli Exo I digestion efficiently and selectively removes surplus reverse transcription primer and thereby reduces the primer–adapter product contamination in 3′ cDNA ligation-based sequencing libraries, including small RNA libraries, which are typically similar in size to the primer–adapter products. We further demonstrate that Exo I treatment does not lead to trimming of the cDNA 3′ end when duplexed with the RNA template. Exo I digestion is easy to perform and implement in other protocols and could facilitate a more widespread use of 3′ cDNA ligation for sequencing-based applications.

scholarly journals Comprehensive assessment of multiple biases in small RNA sequencing reveals significant differences in the performance of widely used methods

2018 ◽  
Author(s):  
Carrie Wright ◽  
Anandita Rajpurohit ◽  
Emily E. Burke ◽  
Courtney Williams ◽  
Leonardo Collado-Torres ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
High Throughput ◽  
Small Rna ◽  
Reverse Transcription ◽  
High Throughput Sequencing ◽  
Small Rna Sequencing ◽  
Library Preparation ◽  
Adapter Ligation ◽  
Improve Accuracy ◽  
Reliable Quantification

ABSTRACTHigh-throughput sequencing offers advantages over other quantification methods for microRNA (miRNA), yet numerous biases make reliable quantification challenging. Previous evaluations of the biases associated with small RNA sequencing have focused on adapter ligation bias with limited evaluation of reverse transcription or amplification biases. Furthermore, evaluations of the accuracy of quantifications of isomiRs (miRNA isoforms) or the influence of starting amount on performance have been very limited and no study has yet evaluated differences in the quantification of isomiRs of altered length. In addition, no studies have yet compared the consistency of results derived from multiple moderate starting inputs. We therefore evaluated quantifications of miRNA and isomiRs using four library preparation kits, with various starting amounts, as well as quantifications following removal of duplicate reads using unique molecular identifiers (UMIs) to mitigate reverse transcription and amplification biases. All methods resulted in false isomiR detection; however, the adapter-free method tested was especially prone to false isomiR detection. We demonstrate that using UMIs improves accuracy and we provide a guide for input amounts to improve consistency. Our data show differences and limitations of current methods, thus raising concerns about the validity of quantification of miRNA and isomiRs across studies. We advocate for the use of UMIs to improve accuracy and reliability of miRNA quantifications.

scholarly journals Bias in Ligation-Based Small RNA Sequencing Library Construction Is Determined by Adaptor and RNA Structure

PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0126049 ◽  
Author(s):  
Ryan T. Fuchs ◽  
Zhiyi Sun ◽  
Fanglei Zhuang ◽  
G. Brett Robb
Keyword(s):  
Rna Sequencing ◽  
Small Rna ◽  
Rna Structure ◽  
Small Rna Sequencing ◽  
Library Construction ◽  
Sequencing Library

RNA sequencing library construction for Illumina GA II v1

protocols.io ◽  
2015 ◽  
Author(s):  
Jian Cao ◽  
Julie Ni ◽  
Wenxiu Ma ◽  
Vanessa Shiu ◽  
Luis A ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
Library Construction ◽  
Sequencing Library

scholarly journals Characterization of Human Salivary Extracellular RNA by Next-generation Sequencing

2018 ◽  
Vol 64 (7) ◽  
pp. 1085-1095 ◽  
Author(s):  
Feng Li ◽  
Karolina Elżbieta Kaczor-Urbanowicz ◽  
Jie Sun ◽  
Blanca Majem ◽  
Hsien-Chun Lo ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
Data Storage ◽  
Small Rna ◽  
Small Rnas ◽  
Rna Isolation ◽  
Small Rna Sequencing ◽  
Rna Seq ◽  
Extracellular Rna ◽  
Library Construction ◽  
Rrna Depletion

Abstract BACKGROUND It was recently discovered that abundant and stable extracellular RNA (exRNA) species exist in bodily fluids. Saliva is an emerging biofluid for biomarker development for noninvasive detection and screening of local and systemic diseases. Use of RNA-Sequencing (RNA-Seq) to profile exRNA is rapidly growing; however, no single preparation and analysis protocol can be used for all biofluids. Specifically, RNA-Seq of saliva is particularly challenging owing to high abundance of bacterial contents and low abundance of salivary exRNA. Given the laborious procedures needed for RNA-Seq library construction, sequencing, data storage, and data analysis, saliva-specific and optimized protocols are essential. METHODS We compared different RNA isolation methods and library construction kits for long and small RNA sequencing. The role of ribosomal RNA (rRNA) depletion also was evaluated. RESULTS The miRNeasy Micro Kit (Qiagen) showed the highest total RNA yield (70.8 ng/mL cell-free saliva) and best small RNA recovery, and the NEBNext library preparation kits resulted in the highest number of detected human genes [5649–6813 at 1 reads per kilobase RNA per million mapped (RPKM)] and small RNAs [482–696 microRNAs (miRNAs) and 190–214 other small RNAs]. The proportion of human RNA-Seq reads was much higher in rRNA-depleted saliva samples (41%) than in samples without rRNA depletion (14%). In addition, the transfer RNA (tRNA)-derived RNA fragments (tRFs), a novel class of small RNAs, were highly abundant in human saliva, specifically tRF-4 (4%) and tRF-5 (15.25%). CONCLUSIONS Our results may help in selection of the best adapted methods of RNA isolation and small and long RNA library constructions for salivary exRNA studies.

Small RNA Sequencing to Discover Circulating MicroRNA Biomarkers of Testicular Toxicity in Dogs

2020 ◽  
pp. 109158182096151
Author(s):  
Jennifer C. Shing ◽  
Kai Schaefer ◽  
Shaun E. Grosskurth ◽  
Andy H. Vo ◽  
Tatiana Sharapova ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
Small Rna ◽  
Exploratory Study ◽  
Quantitative Polymerase Chain Reaction ◽  
Small Rna Sequencing ◽  
Circulating Microrna ◽  
Testicular Toxicity ◽  
Potential Candidate ◽  
Drug Induced ◽  
Organ Systems

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.

scholarly journals Methyltransferase-directed orthogonal tagging and sequencing of miRNAs and bacterial small RNAs

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Milda Mickutė ◽  
Kotryna Kvederavičiūtė ◽  
Aleksandr Osipenko ◽  
Raminta Mineikaitė ◽  
Saulius Klimašauskas ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
Regulatory Networks ◽  
Library Preparation ◽  
Rna Seq ◽  
Basic Principles ◽  
Cofactor Binding ◽  
Sequencing Library ◽  
Sequencing Library Preparation ◽  
Target Rna

Abstract Background Targeted installation of designer chemical moieties on biopolymers provides an orthogonal means for their visualisation, manipulation and sequence analysis. Although high-throughput RNA sequencing is a widely used method for transcriptome analysis, certain steps, such as 3′ adapter ligation in strand-specific RNA sequencing, remain challenging due to structure- and sequence-related biases introduced by RNA ligases, leading to misrepresentation of particular RNA species. Here, we remedy this limitation by adapting two RNA 2′-O-methyltransferases from the Hen1 family for orthogonal chemo-enzymatic click tethering of a 3′ sequencing adapter that supports cDNA production by reverse transcription of the tagged RNA. Results We showed that the ssRNA-specific DmHen1 and dsRNA-specific AtHEN1 can be used to efficiently append an oligonucleotide adapter to the 3′ end of target RNA for sequencing library preparation. Using this new chemo-enzymatic approach, we identified miRNAs and prokaryotic small non-coding sRNAs in probiotic Lactobacillus casei BL23. We found that compared to a reference conventional RNA library preparation, methyltransferase-Directed Orthogonal Tagging and RNA sequencing, mDOT-seq, avoids misdetection of unspecific highly-structured RNA species, thus providing better accuracy in identifying the groups of transcripts analysed. Our results suggest that mDOT-seq has the potential to advance analysis of eukaryotic and prokaryotic ssRNAs. Conclusions Our findings provide a valuable resource for studies of the RNA-centred regulatory networks in Lactobacilli and pave the way to developing novel transcriptome and epitranscriptome profiling approaches in vitro and inside living cells. As RNA methyltransferases share the structure of the AdoMet-binding domain and several specific cofactor binding features, the basic principles of our approach could be easily translated to other AdoMet-dependent enzymes for the development of modification-specific RNA-seq techniques.

scholarly journals Small RNA-Sequencing: Approaches and Considerations for miRNA Analysis

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 964
Author(s):  
Sarka Benesova ◽  
Mikael Kubista ◽  
Lukas Valihrach
Keyword(s):  
Rna Sequencing ◽  
Small Rna ◽  
High Sensitivity ◽  
Small Rna Sequencing ◽  
Rna Seq ◽  
Liquid Biopsies ◽  
Comprehensive Overview ◽  
Rna Molecules ◽  
Novel Mirna ◽  
The Many

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.

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