Progress in circular RNAs of plants / 生物工程学报

With the development of high-throughput sequencing technology, circular RNAs (circRNAs) have gradually become a hotspot in the research on non-coding RNA. CircRNAs are produced by the covalent circularization of a downstream 3' splice donor and an upstream 5' splice acceptor through backsplicing, and they are pervasive in eukaryotic cells. CircRNAs used to be considered byproducts of false splicing, whereas an explosion of related studies in recent years has disproved this misconception. Compared with the rich studies of circRNAs in animals, the study of circRNAs in plants is still in its infancy. In this review, we introduced the discovery of plant circRNAs, the discovery of plant circRNAs, the circularization feature, expression specificity, conservation, and stability of plant circRNAs and expounded the identification tools, main types, and biogenesis mechanisms of circRNAs. Furthermore, we summarized the potential roles of plant circRNAs as microRNA (miRNA) sponges and translation templates and in response to biotic/abiotic stress, and briefed the degradation and localization of plant circRNAs. Finally, we discussed the challenges and proposed the future directions in the research on plant circRNAs.

Progress in Research on the Novel Tumor Marker circRNA / 中国医学科学院学报

Circular RNA(circRNA)is a novel type of endogenous non-coding RNA.Most circRNAs act as microRNA(miRNA)sponges to regulate the expression of functional genes.In addition,some circRNAs can be translated and interact with RNA-binding proteins to perform biological functions.The expression of circRNAs is prevalent in tissues and body fluids,and their abnormal expression is related to tumor progression.circRNAs are stable even under the treatment of RNase R because of their circular conformation.As circRNAs have construct stability,wide variety,specific regulation of tumor progression and high expression in body fluids,it is potential for circRNAs to serve as candidate diagnostic,prognostic and therapeutic targets.However,the knowledge about circRNAs remains poor.In addition to the not completely resolved functions and generation mechanisms of circRNAs,the annotations of circRNAs are also waiting for expanding.Here,we review the generation mechanisms,biological functions,and application of circRNAs in tumor research,aiming to provide integrated information for the future research.

CIRCpedia v2: An Updated Database for Comprehensive Circular RNA Annotation and Expression Comparison / 基因组蛋白质组与生物信息学报·英文版

Circular RNAs (circRNAs) from back-splicing of exon(s) have been recently identified to be broadly expressed in eukaryotes, in tissue- and species-specific manners. Although functions of most circRNAs remain elusive, some circRNAs are shown to be functional in gene expression regulation and potentially relate to diseases. Due to their stability, circRNAs can also be used as biomarkers for diagnosis. Profiling circRNAs by integrating their expression among different samples thus provides molecular basis for further functional study of circRNAs and their potential application in clinic. Here, we report CIRCpedia v2, an updated database for comprehensive circRNA annotation from over 180 RNA-seq datasets across six different species. This atlas allows users to search, browse, and download circRNAs with expression features in various cell types/tissues, including disease samples. In addition, the updated database incorporates conservation analysis of circRNAs between humans and mice. Finally, the web interface also contains computational tools to compare circRNA expression among samples. CIRCpedia v2 is accessible at http://www.picb.ac.cn/rnomics/circpedia.