Scientists have discovered a new role in cancer protection for an already well-known tumor suppressor protein. The protein, called p53, protects cells from becoming cancerous by sensing stress and either shutting down cell division or triggering cell death. Researchers at the University of Tokyo and colleagues have discovered that p53 also plays a role in slicing stretches of RNA into regulatory molecules called microRNAs (SN: 8/15/09, p. 8). Mutations of the gene for p53 prevent proper assembly of microRNA-processing machinery, the researchers found.
MicroRNAs are tiny, containing only about 22 nucleotides, or chemical letters. But the molecules have a big influence on nearly every aspect of cellular function. The absence of some microRNAs has recently been linked to cancers. Researchers at Johns Hopkins University, along with others, replaced a microRNA missing from liver canc