Bacteria slow their DNA repair to a crawl in favor of proofreading RNA gene transcripts

Jordana Cepelewicz writes: Evolution is a game of trade-offs. Every trait an organism inherits may have benefits and drawbacks; what matters to natural selection is whether the trait is positive or negative on balance. But in a recent study, researchers described a balancing act that seems more counterintuitive than most: Bacterial cells prioritize transcription — the process of making RNA transcripts of genes as the first step in protein production — over repairing double-strand breaks in their DNA.

“We tend to think of DNA as the brains of the cell,” said Susan Rosenberg, a biologist at Baylor College of Medicine in Houston. “If we push that analogy and think about parts of the cell competing for resources the way the parts of the body do, the brain should be getting whatever it needs at the expense of everything else.”

So when her Baylor colleague Christophe Herman approached her with the hypothesis that transcription might be more important than DNA repair, Rosenberg was ready to bet the other way. “And I was sure I would win,” she said.

But she was proven wrong. Last month, she, Herman and their team published the results of their research in Nature: They found, using a series of experiments and intricate controls, that transcription can trump DNA repair in E. coli. [Continue reading…]

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