BEIJING, March 23 (Xinhua) -- Chinese researchers have built an open database on Circular RNAs, laying the groundwork for studies on the novel class of RNAs with important biological implications.

RNA comes in many shapes and sizes. In recent years, Circular RNAs (circRNAs), a type of RNAs beyond the textbook classics, are of huge interest to many molecular biologists.

Unlike linear RNAs, the nucleotides of circRNA are arranged in a closed loop. Previous studies found that circRNAs could play important roles in gene regulation, development and formation of cancers, but the understanding of how circRNAs participate in these biological processes is still preliminary.

Comprehensive detection and reconstruction of circRNAs is an initial step to study their function. Researchers from Beijing Institute of Life Sciences, Chinese Academy of Sciences sequenced 44 normal tissue samples from human, macaque and mouse, and identified large numbers of circRNAs, about 94,461 circRNAs per species.

The Chinese researchers reported online on the international journal of Cell Reports that they developed a tool named CIRI-full and achieved full-length reconstruction of 72.6 percent of the identified circRNAs.

They used the method and the data in studying liver cancer and successfully identified circRNAs that are related to the formation of liver cancer.

A database "circAtlas" (//circatlas.biols.ac.cn) was then built to make the research data open to other scientists on circRNAs. The database integrated millions of circRNAs across seven species, namely human, macaque, mouse, rat, pig, chicken and dog.

Functional annotations were also added and promising functional circRNA candidates were prioritized for further studies.

The researchers said their study provided a comprehensive view of circRNAs in mammals and laid the groundwork for future circRNA studies.