miR-150, a microRNA expressed in mature B and T cells, blocks early B cell development when expressed prematurely

• DOI: 10.1073/pnas.0702409104
• Publication Date: 2007-04-17T00:54:21Z
• Authors: Beiyan Zhou; Stephanie Wang; Christine Mayr; David P. Bartel; Harvey F. Lodish
• Keywords: Mice, Inbred C57BL; 0301 basic medicine; B-Lymphocytes; Mice; MicroRNAs; 03 medical and health sciences; Time Factors; Gene Expression Regulation; T-Lymphocytes; Animals

MicroRNAs (miRNAs) are a family of ≈22-nt noncoding RNAs that can posttranscriptionally regulate gene expression. Several miRNAs are specifically expressed in hematopoietic cells. Here we show that one such miRNA, miR-150, is mainly expressed in the lymph nodes and spleen and is highly up-regulated during the development of mature T and B cells; expression of miR-150 is sharply up-regulated at the immature B cell stage. Overexpression of miR-150 in hematopoietic stem cells, followed by bone marrow transplantation, had little effect on the formation of either mature CD8- and CD4-positive T cells or granulocytes or macrophages, but the formation of mature B cells was greatly impaired. Furthermore, premature expression of miR-150 blocked the transition from the pro-B to the pre-B stage. Our results indicate that miR-150 most likely down-regulates mRNAs that are important for pre- and pro-B cell formation or function, and its ectopic expression in these cells blocks further development of B cells.