[
Science,
2001]
RNA molecules are a constant source of joy to molecular biologists: They come in all shapes and sizes, and perform diverse informational, structural, and catalytic tricks in living cells. Perhaps less appreciated is their facility for regulating gene expression. Small regulatory RNAs figure prominently in two fascinating phenomena: gene inactivation by RNA interference (RNAi), and the control of gene expression during development.
[
Science,
2001]
Over the years, a steady stream of structural and regulatory RNAs have been identified. Three papers published in this issue on pages 853, 858, and 862 from the Tuschl, Bartel, and Ambros labs continue the tradition, but now prospecting for tiny RNAs of 22 nucleotides (nt). The chain of reasoning that simultaneously attracted these groups to 22 nt is convoluted but interesting.