Fig. 1

PTBP1 was screened as a key RBP for the regulation of circRNA. A CircRNAs identified from 10 cell lines in ENCODE project and co-expressed in other cell lines. Different colors represent circRNAs expressed in 1, 2 ~ 4, 5 ~ 7, and 8 ~ 10 cell lines, respectively. B CircRNA co-expression networks. Each node represents a circRNA, and the node color indicates the cell line with the highest expression level of the circRNA. Each edge represents the Pearson correlation coefficient greater than 0.9 between two circRNAs. C Numbers of RBP motifs in circRNA flanking introns in 10 cell lines. The x-axis represents different RBPs. Different colors of the lines represent different cell lines. D Gene expression levels of the top RBPs with the largest numbers of motifs. FPKM was obtained from the ENCODE project. Four cell lines with the largest numbers of RBP motifs were demonstrated. E Length distribution of circRNA flanking introns identified in K562 cell line with or without the PTBP1 motifs. F Pearson correlation coefficient between PTBP1 and circRNAs across 10 cell lines