What Are miRNAs Good For?

Science's STKE  12 Jul 2005:
Vol. 2005, Issue 292, pp. tw260
DOI: 10.1126/stke.2922005tw260

MicroRNAs (miRNAs) are small ~22-nucleotide noncoding RNAs that play a role in posttranscriptionally regulating target gene expression. Many miRNA genes have been found in both plant and animal genomes, and recent work has suggested that miRNAs may be involved in cell differentiation and morphogenesis, rather than in fate specification. Wienholds et al. examined the in situ expression patterns of 115 miRNAs in zebrafish embryos, miRNAs that are also conserved in mice and humans. In many cases, the patterns were highly tissue- and cell-specific, consistent with a general role for miRNAs in cell differentiation. Expression was not seen before segment formation, as expected if miRNAs do not promote tissue establishment.

E. Wienholds, W. P. Kloosterman, E. Miska, E. Alvarez-Saavedra, E. Berezikov, E. de Bruijn, H. R. Horvitz, S. Kauppinen, R. H. A. Plasterk, MicroRNA expression in zebrafish embryonic development. Science 309, 310-311 (2005). [Abstract] [Full Text]