Online Databases and Circular RNAs

circRNAs are a novel class of ncRNAs that unlike other ncRNAs are not linear and have a circular structure. These valuable ncRNAs have been detected in a wide range of organisms from plants to animals and in all cell lines and tissues. Commonly, circRNAs have several functions as gene expression regulation at transcriptional or posttranscriptional level, miRNA partnership, and splicing intercede. Currently, circRNAs are roughly remarked in a widespread collection of diseases, and circRNAs simply can be recognized in liquid samples for disease detection and progression assessment. Considering these features of circRNAs, these molecules are evolving the impeccable collection of original biomarkers for disease therapy and diagnosis. As the critical role of these molecules in different aspects medicine and biology, circRNAs are considered as key and critical class of ncRNA in the current ncRNA search field. To simplify the assessment of diverse features of circRNAs, several databases have been established such as circBase, CircInteractome, CircNet, Circ2Traits, CircR2Disease, TCSD, and CSCD. In this chapter, we have an overview on these main circRNA databases and introduce key features of each database.