Molecular Biology

RNA Traffic

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Science  24 Jun 2005:
Vol. 308, Issue 5730, pp. 1845
DOI: 10.1126/science.308.5730.1845b

Both yeast and mammalian cells exhibit a handful of cytoplasmic sites referred to as processing bodies (P bodies), where enzymes that catalyze hydrolytic reactions, such as decapping and deadenylation, in the process of mRNA degradation can be found. Three groups have extended the list of components that congregate at these foci.

Andrei et al. show that eukaryotic initiation factor 4E (eIF4E), which binds to the cap at the 5' end of the mRNA, and one of its binding partners (eIF4E-T) localize to P bodies. They suggest that these two factors combine to inhibit translation (the initiation stage of translation depends on eIF4E being free to interact with eIF4G) of mRNAs residing in P bodies. Sen and Blau, and Liu et al., report that P bodies contain Argonaute 2, the endonuclease of the RNA-induced silencing complex (RISC), and the latter group find microRNAs (miRNAs) in complex with their target mRNAs there, too. These observations suggest that both the cleavage of mRNAs triggered by small interfering RNAs (siRNAs) and the translational repression of mRNAs induced by miRNAs may depend on trafficking of protein-RNA complexes into P bodies. — GJC

RNA 11, 717 (2005); Nat. Cell Biol. 7, 633; 10.1038/ncb1274 (2005).

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