Mutation of DNA by chemical reactions is an ever-present threat to living organisms and, as the temperature rises, the common DNA-damaging reactions increase dramatically. The temperature divas of the living world are the hyperthermophilic archaea, heat-loving microorganisms that thrive in boiling springs and volcanic craters. But despite much searching, no-one has yet found any indication of how these tiny microorganisms prevent their DNA from becoming irreversibly scrambled by the heat.
Martin Greagg from University College London, UK and colleagues have now come up with a likely mechanism for protection against one of the commonest chemical reactions that damage DNA. This is the conversion of cytosine bases in DNA to another base, uracil, by a spontaneous reaction that removes an amino group from the cytosine. When DNA altered in this way is replicated, the uracil will direct incorrect incorporation of an adenine, rather than a cytosine, into the new DNA strand at this position. The result is that half of all the descendants of that cell will be mutant.
This is a preview of subscription content, access via your institution