TY - JOUR T1 - A CLEAR pipeline for direct comparison of circular and linear RNA expression JF - bioRxiv DO - 10.1101/668657 SP - 668657 AU - Xu-Kai Ma AU - Meng-Ran Wang AU - Chu-Xiao Liu AU - Rui Dong AU - Gordon G. Carmichael AU - Ling-Ling Chen AU - Li Yang Y1 - 2019/01/01 UR - http://biorxiv.org/content/early/2019/06/12/668657.abstract N2 - Sequences of circular RNAs (circRNAs) produced from back-splicing of exon(s) completely overlap with sequences from cognate linear RNAs transcribed from the same gene loci with the exception of their back-splicing junction (BSJ) sites. Examination of global circRNA expression from RNA-seq datasets generally relies on the detection of RNA-seq fragments spanning BSJ sites, but a direct comparison of circular and linear RNA expression from the same gene loci in a genome-wide manner has remained challenging. This is because quantification of BSJ fragments differs from that of linear RNA expression that uses normalized RNA-seq fragments mapped to the whole gene bodies. Here, we have developed a computational pipeline for circular and linear RNA expression analysis from ribosomal-RNA depleted RNA-seq (CLEAR, https://github.com/YangLab/CLEAR). A new quantitation parameter, FPB (fragments per billion mapped bases), is applied to evaluate circular and linear RNA expression individually by fragments mapped to circRNA-specific BSJ sites or to linear RNA-specific splicing junction (SJ) sites. Then, circular and linear RNA expression are directly compared by dividing FPBcirc by FPBlinear to generate a CIRCscore, which indicates the relative circRNA expression using linear RNA expression as the background. Highly-expressed circRNAs with low cognate linear RNA expression background can be identified for further investigation. ER -