RNA's role inblood coagulation

If you thought RNA's responsibility in a cell was limited to orchestrating and silencing the conversion of DNA into proteins, think again. Researchers have found that RNA also plays a part in coagulating blood near a wound. When a cut severs the cell lining of a vein, blood components called platelets race to the scene to physically stem blood loss. Next, a complex series of enzymes coagulate blood and catalyze fibrin formation to tightly seal the wound, a necessary step in tissue repair. Klaus T. Preissner, a biochemist at Justus Liebig University, in Germany, and his colleagues show that RNA that has spilled out from damaged cells helps to activate two coagulation enzymes called factor XII and factor XI (Proc. Natl. Acad. Sci. USA 2007, 104, 6388). The researchers find that adding an enzyme that breaks down RNA impedes these repair proteins from doing their job. Furthermore, injecting RNA into animal models initiates coagulation.