RT Journal Article SR Electronic T1 MicroRNAs Modulate Hematopoietic Lineage Differentiation JF Science JO Science FD American Association for the Advancement of Science SP 83 OP 86 DO 10.1126/science.1091903 VO 303 IS 5654 A1 Chen, Chang-Zheng A1 Li, Ling A1 Lodish, Harvey F. A1 Bartel, David P. YR 2004 UL http://science.sciencemag.org/content/303/5654/83.abstract AB MicroRNAs (miRNAs) are an abundant class of ∼22-nucleotide regulatory RNAs found in plants and animals. Some miRNAs of plants, Caenorhabditis elegans, and Drosophila play important gene-regulatory roles during development by pairing to target mRNAs to specify posttranscriptional repression of these messages. We identify three miRNAs that are specifically expressed in hematopoietic cells and show that their expression is dynamically regulated during early hematopoiesis and lineage commitment. One of these miRNAs, miR-181, was preferentially expressed in the B-lymphoid cells of mouse bone marrow, and its ectopic expression in hematopoietic stem/progenitor cells led to an increased fraction of B-lineage cells in both tissue-culture differentiation assays and adult mice. Our results indicate that microRNAs are components of the molecular circuitry that controls mouse hematopoiesis and suggest that other microRNAs have similar regulatory roles during other facets of vertebrate development.