CircRNAome diversity in human mature B-cells, T-cells and monocytes

Circular RNAs (circRNAs) were shown to be expressed in all human tissue but detailed insight in circRNA diversity among tissues and cellular differentiation stages is lagging behind. This study provides comprehensive data on circRNA expression in the three major mature blood cell populations of healthy subjects. Over 36,000 circRNAs were identified in B-cells, T-cells and monocytes, 34% of which were novel. In addition, putative new genes producing circRNAs were uncovered. The definition of cell type specific circRNA expression signatures revealed that alternative circularization is a common phenomenon showing cell population specific patterns. Abundance of circRNAs resulted largely uncorrelated to host gene linear expression. Several circRNAs were validated, including circular isoforms expressed by leukemia-associated genes PAX5 and IKZF1. These results and new data will help to further our understanding of molecular mechanisms underlying cell biology of blood cells, and are a reference to explore circRNA alterations in haematological diseases. Mononuclear cells were isolated from peripheral blood of healthy adult donors. CD45+ population was separated into B-cells, T-cells and monocytes, after labeling with anti CD19, CD3, CD14 antibodies. For each cell type, 4 biological replicates were obtained from different donors. Total RNA was extracted and used for RNA-seq.