An Interfering Ego?

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Science  10 Mar 2000:
Vol. 287, Issue 5459, pp. 1713
DOI: 10.1126/science.287.5459.1713g

Posttranscriptional gene silencing (PTGS) is a poorly understood form of gene regulation that can be triggered when foreign nucleic acid is introduced into an organism, and that has been observed in plants, fungi, flies, and nematodes. PTGS involves activation of a sequence-specific mechanism of RNA turnover that results in reduced expression of endogenous genes. The proposed mechanism relies on an RNA-dependent RNA polymerase (RdRP), and, in agreement with this model, PTGS in Neurospora was recently shown to require a protein called QDE-1, which is related to RdRPs.

Work by Smardon et al. adds the tantalizing suggestion that RdRP-mediated PTGS may play a fundamental role in animal development. These authors find that ego-1, a gene required for germline development in the nematode Caenorhabditis elegans, encodes a protein with sequence homology to RdRPs and to QDE-1, and that a subset of germline-specific genes are resistant to RNA interference (a form of PTGS) in ego-1 mutants. Further genetic analyses may lead to a better understanding of RdRPs, enzymes that have been studied intensively in the context of RNA viruses but whose function and even existence in eukaryotic cells has been debated.—PAK

Curr. Biol.10, 169 (2000).

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