Human DNA Sentry Keeps Long Strands Atop Watch List

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 D