Profiles analysis reveals circRNAs involving zebrafish physiological development

Recent studies have found that known functions of circRNAs include sequestration of microRNAs or proteins, modulation of transcription and interference with splicing, and even translation to produce poly-peptides. The zebrafish model is also demonstrably similar to humans in many studies. In order to explore the changes in circRNAs during embryonic development, further to research the mechanism of action of circRNAs in development-related diseases. Zebrafish embryos at blastula period, gastrula period, segmentation period, throat stage and incubation period were collected. Illumina deep sequencing technology and CIRI algorithm were used to detecting circRNAs. Totally we identified 1028 circRNAs (junction reads ≥ 5 and p < 0.05). Considering that circRNAs function is related to host genes, then bioinformatics analysis revealed these differentially expressed host genes are involved in NOTCH signaling pathways, cardiovascular system development, retinal ganglion cell axon guidance and so on. Moreover, circRNAs can participate in biological regulation through miRNA sponges function. TargetScan and miRanda were used to predict 73 miRNAs binding to circRNAs such as miR-19b, miR-124 and so on, some miRNAs play important roles in embryogenesis. The peak expression of circRNAs is distributed at different time points, suggesting that it may be involved in embryogenesis at different stages. Our study provides a foundation for understanding the dynamic regulation of circRNA transcriptomes during embryogenesis and identifies novel key circRNAs that might control embryonic development in zebrafish model. circRNAs of five periods (blastula, gastrula, segmentation, throat and incubation) in zebrafish were detected by deep sequencing using Illumina HiSeq 2500.