Researchers at MIT have uncovered a unique bacterial self-defense mechanism that could have implications for human virology, as reported by MIT News. The newfound CmdTAC system in bacteria serves as a countermeasure to phage, a virus that infects and replicates within these unicellular organisms. According to the study, bacteria can detect viral infection and respond by activating the CmdTAC complex, which subsequently halts protein production and thwarts the progression of the infection.
Led by Michael Laub, the team at the Laub Lab has detailed this anti-phage defense, which relies on an enzyme called ADP-ribosyltransferase. This enzyme modifies bacterial messenger RNA, specifically targeting GA sequences to stop translation and protein creation. Co-author Christopher Vassallo explained that this microbial self-sacrifice is crucial for bacterial colony survival.
CmdTAC belongs to a broader class of toxin-antitoxin (TA) systems commonly found in bacteria. It adds a new layer to bacterial defense by introducing CmdC, a chaperone that senses infection and releases the toxin, triggering cell death. Co-first author Christopher Doering noted that TA systems, though recently studied, are essential in anti-phage defense.
CmdTAC may represent a small part of an evolutionary puzzle with broader implications. The enzyme responsible for mRNA modification resembles those in eukaryotes, including humans. “There are so many different — and cool — mechanisms by which organisms defend themselves against viral infection,” Laub stated, adding that these defenses could shed light on how human bodies combat viruses.
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