Out-of-place DNA arouses the suspicion of a mammalian protein called cGAS, or cyclic GMP-AMP synthase. Although cGAS is usually as passive as a bored security guard, it leaps into action when it comes across DNA in the cell’s cytosol. Such DNA may indicate a foreign or cancerous intrusion. Curiously, the human version of cGAS has unique structural features that keep it on the lookout for long sequences. Short sequences often get a pass. The advantages of a bias against long pieces of stray DNA aren’t exactly clear. Perhaps the bias helps prevent autoimmune disorders. In any case, the structural details behind the bias could inform the development of immunotherapeutic drugs, including drugs to combat cancer. Contributing to a deeper understanding of these issues is a recent study conducted by scientists at Harvard Medical School and the Dana-Farber Cancer Institute. These scientists have, for the first time, ...
Original Article: Human DNA Sentry Keeps Long Strands atop Watch List