A bacterial defense copies DNA in repeats, the way telomerase does

The article, “Antiviral immunity via telomerase-like reverse transcription in bacteria,” was published Oct. 12, 2026. The corresponding authors are Stephen Tang and Samuel H. Sternberg of Columbia University and Israel S. Fernández of the University of the Basque Country. Other authors are at Columbia, the Howard Hughes Medical Institute, the University of Copenhagen, and the Simons Electron Microscopy Center in New York.

Defense-associated reverse transcriptases, the abstract says, already use several ways of making DNA from RNA to protect bacteria from viruses. Many of those ways are still unknown. DRT10 pairs the enzyme with a noncoding RNA and builds tandem-repeat DNA, primed by a protein rather than by a snippet of nucleic acid. A defined stretch of that RNA is the template. The pattern of the template, and the boundary marks at its edges, are conserved, and the experiments say both are required.

Cryo-electron microscopy, a way of freezing molecules and reading their shape, shows two copies of the enzyme on opposite sides of an RNA that looks symmetric. Each copy reads the template on its own side. Only one of them makes the long repetitive product. The length of that template is the distance between two stem-loops, folds in the RNA that act as anchors.

The authors say this start-and-stop, boundary-limited copying is a direct parallel to how telomerase adds telomeric repeats. Their family tree places telomerase in one clade with the DRT family. Together with earlier work on three related systems, DRT2, DRT3, and DRT9, they say the same logic of RNA-templated DNA repeats shows up across these defenses even when the shapes of the machines differ.

The abstract is the source for every mechanistic sentence above. This desk did not open the supplementary files or the full text beyond the abstract and the author block.