Built-in 'self-destruct timer' kills messenger RNA in cells
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Researchers have discovered the first known mechanism by which cells control the survival of messenger RNA (mRNA). Because mRNA helps regulate cell division, this discovery could be used to reverse cancer's out-of-control cell division. To make proteins, a gene's DNA must be copied onto mRNA molecules, which migrate from the nucleus to the cell’s protein factories in the cytoplasm. Scientists have long suspected that cells must have ways for degrading mRNA when enough of a protein has been made. In their search for this mechanism, the researchers found two specific genes whose mRNAs are, in effect, born with molecular "self-destruct timers." The scientists found that the promoter regions of these genes recruit a protein called Dbf2p, which jumps onto mRNA molecules as they are being synthesized. After these mRNAs make their journey to the cytoplasm, a protein called Dbf20p joins Dbf2p aboard the mRNA molecules—and the two proteins together call for the molecules' precipitous decay.