Cell Biology

Quick-Release RNA

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Science  21 Oct 2005:
Vol. 310, Issue 5747, pp. 409
DOI: 10.1126/science.310.5747.409c

After it is transcribed from DNA, eukaryotic messenger RNA (mRNA) undergoes various types of processing, including the addition of a polyadenylate [poly(A)] tail. The mRNA then typically moves out of the nucleus and into the cytoplasm, where it is translated into protein. However, a large fraction of poly(A)+ RNA stays within the nucleus.

Prasanth et al. now suggest that this nuclear-retained RNA may be part of a gene-regulatory mechanism that ensures rapid translation of mRNAs that are required for cellular defenses against stress. They found two populations of poly(A)+ RNA derived from the mouse gene encoding cationic amino acid transporter 2, a protein critical for the activation of the nitric oxide signaling pathway (a common response to stress). In addition to the conventional protein-coding mCAT2 mRNA present in the cytoplasm, a second transcript (CTN-RNA) was retained in the nucleus by virtue of its distinct 3' untranslated region (UTR). When cells were exposed to stress, the latter RNA was rapidly cleaved at its 3'UTR and released into the cytoplasm. This nuclear RNA release mechanism may thus control the expression of a variety of proteins whose activity is required rapidly in response to stress or other cellular signals. — PAK

Cell, in press.

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