To support the recent emerging of circular RNA (circRNA) research, CD Genomics is providing the circRNA sequencing service that utilizes the latest Illumina platforms for a fast, economical, and accurate characterization.
The Introduction of CircRNA Sequencing
CircRNA is a novel member of the non-coding RNAs (ncRNAs), generated by non-sequential backsplicing of exons, introns or both. They are characterized by covalently closed loop feature thus lacking 5' end caps and 3' poly-A tails. CircRNAs are highly stable forms of ncRNAs due to their nuclease resistance properties. When first identified in the 1970s, circRNAs were regarded as viral genomes or byproducts of mis-splicing events. But the recent researches have revealed that circRNAs are evolutionarily conserved across plants, animals, and human beings, and that circRNAs have important biological functions.
CircRNAs may act as miRNA sponges and fulfill a regulatory function in gene expression. Remarkably, a wide range of circRNAs are abnormally expressed in specific disease contexts, which suggests their association with the occurrence and development of human diseases. CircRNAs also perform multiple functions in cellular processes including templates for translation, regulation of alternative splicing and gene expression, scaffolds for the assembly of protein complexes, and modulator of rRNA and tRNA biogenesis. Additionally, they can be used to boost immune activation for antiviral therapeutic purposes due to their intervention in immune regulation and viral infection.
Comprehensive detection of circRNAs from high-throughput transcriptome data is an initial and crucial step to study their biogenesis and function. The high-throughput sequencing of rRNA/linear RNA-depleted RNA in combination with computational tools has led to the identification of thousands of new circRNAs and analysis of their linear host transcripts in a quantitative manner in diverse organisms. Unlike miRNAs and other small RNAs, circRNAs are not easily separated from other RNA species by size or electrophoretic mobility. Consequently, they are generally retained in rRNA-depleted libraries and enriched in libraries treated with RNase R that only digest linear RNA.
Advantages of CircRNA Sequencing
Identifies known and novel circRNAs
Allows profiling of circRNAs across a wide dynamic ranges
Explores novel biomarkers and circRNAs regulatory networks
Applications of CircRNA Sequencing
CircRNA sequencing can be used for but not limited to the following research:
Investigating the pathogenic mechanisms of diseases such as cancer;
Exploring gene expression regulatory changes during growth and development;
Researching other aspects related to gene transcription and expression regulation.
CircRNA Sequencing Workflow
The general workflow for circRNA sequencing is outlined below. To construct circRNA sequencing library, the first step is to deplete rRNA, followed by linear RNA digestion and strand-specific library preparation. Our highly experienced expert team executes quality management, following every procedure to ensure confident and unbiased results.
Data Analysis We provide multiple customized bioinformatics analyses:
Raw data quality control
Reference-based mapping
CircRNA identification and annotation
Known and novel circRNA expression analysis
Differential expression analysis, enrichment analysis, and functional analysis
Origin analysis of circRNA including target miRNA prediction and circRNA-miRNA interaction network analysis
Note: Recommended data outputs and analysis contents displayed are for reference only. For detailed information, please contact us with your customized requests.
Analysis Pipeline
Deliverables
The original sequencing data
Experimental results
Data analysis report
Details in CircRNA Sequencing for your writing (customization)
Supported by our experienced scientists and advanced technology, CD genomics can help you to acquire the circRNA sequence information with single-base resolution at one time through the high-throughput sequencing by strict quality control and advanced bioinformatics analyses. If you have additional requirements or questions, please feel free to contact us.
Demo Results
Partial results are shown below:
Sequencing quality distribution
A/T/G/C Distribution
IGV Browser Interface
CircRNA Seq FAQs
1. How is circRNA generated?
CircRNAs are generally generated through the back-splicing of exons in a non-sequential order. Circularization of RNA can be generated by repetitive sequences to facilitate the back-splicing of non-sequential exons.
2. Why using high-throughput technology to analyze circRNAs over microarrays?
High-throughput sequencing is a time and cost saving method with many advantages over DNA microarrays.
i. Detection of novel transcripts. Microarrays depend on the hybridization with species or transcript-specific probes that are restricted to known circRNAs. However, RNA sequencing can detect novel transcripts, gene fusions, single nucleotide variants, small insertions and deletions, and other previously unknown changes.
ii. Broader dynamic range. Microarrays are limited by background at the low end and signal saturation at the high end, while RNA sequencing can quantify discrete, digital sequencing read counts, offering a broader dynamic range.
iii. Increased sensitivity and specificity. Compared to microarrays, RNA sequencing offers increased sensitivity and specificity, enabling enhanced detection of genes, transcripts, and differential expression.
iv. Detection of low-abundance and rare transcripts. Sequencing coverage depth can easily be increased for detection of rare transcripts, single transcripts per cell, or weakly expressed genes.
3. Are there any tips for constructing circRNA expression vector of circRNA?
Yes. Sequences for circularization and sequences that activate the circularization are required to construct circRNA expression vector carrying circRNAs.
