Fig. 1: Profiling the alternative circularization to identify predominantly expressed circMAN1A2(2,3,4,5).

a Schematic of alternative circularization (AC) in human transcriptome. b Numbers and percentages of total circRNAs with or without alternative circularization across various cell lines, including HT29, DLD-1, LoVo, HeLa, A549 and 293FT. c Relative abundance of the predominantly expressed circRNAs compared to all circRNAs derived from the same gene locus in examined cell lines. Box plots show the median (center line) and interquartile range (IQR; box), with whiskers extending to the most extreme data points within 1.5 × IQR from the quartiles. RNA-seq was performed in each cell line with two biological replicates. d Overlapped predominantly expressed circRNAs from 16 host genes expressed in all six cell lines. e Volcano plot of differentially expressed circRNAs between normal and colorectal cancer samples among the top 100 predominantly expressed circRNAs. Five significantly upregulated predominantly expressed circRNAs in colorectal cancer samples were ranked by their absolute expression level (right panel). Results shown in (b–e) were derived from ribo– RNA-seq data in GEO under the accession code GSE274247. f Schematic and expression of six confident circMAN1A2 isoforms detected in both normal and colorectal cancer samples. Alu elements with distinct orientations in flanking introns are highlighted by triangles with colors. g Expression rank of all identified circRNAs and their corresponding parental genes in the 20 colon cancer samples. Predominantly expressed circMAN1A2(2,3,4,5) and its cognate MAN1A2 mRNA were highlighted. Results shown in (f and g) were obtained from publicly available paired ribo– RNA-seq data of normal and colon cancer patient samples³⁰, in GSA-Human under accession number PRJCA001113 upon request. h Expression rank of all alternative circularized circRNAs and their corresponding parental genes across various cancer tissues, including COLO, OV, LUAD, PRAD, AML, and BRCA. Predominantly expressed circMAN1A2(2,3,4,5) and its cognate MAN1A2 mRNA were highlighted. Results shown in the (h) were obtained from publicly available exome capture RNA-seq data in the MiOncoCirc database³⁹.