The B2 B-cell lineage and the ncRNA classes present in the depicted developmental stages. (A) A simplified scheme of B2 B-cell development (see supplemental Materials and Methods). Four different ncRNA databases were sequentially queried with our sequencing libraries. Fractions isolated from the BM are shown (B), and (C) depicts the spleen-derived fractions. Pie charts represent the distribution of 8 different classes of small RNAs: unknown indicates not annotated; miRNA, micro-RNA; piRNA, Piwi-interacting RNA; snoRNA, small nucleolar RNA; snRNA, small nuclear RNA; mRNA related, messenger RNA related; tRNA, transfer RNA; and other, other ncRNAs. In general, the distributions are similar to those described in other studies. MLP indicates multipotent lymphoid progenitor; ELP, early lymphoid progenitor; and CLP, common lymphoid progenitor.