DNA replication and repair in halophiles

Abstract

The natural environment inhabited by halophiles results in continual exposure of these organisms to elevated temperatures, fluctuations in oxygen and nutrient concentrations, high levels of solar radiation, and periodic desiccation. Exposure to these conditions results in extensive DNA damage that must be repaired to maintain genomic fidelity and cellular viability. At the same time, DNA replication needs to be highly accurate to prevent the accumulation of mutation and its deleterious effects on the cell's survival. These processes must also allow for errors to generate the diversity required for Darwinian evolution. Studies of DNA replication and repair mechanisms in halophilic archaea, using a combination of biochemical and genetic approaches, have shown to date that these mechanisms bear a great many similarities to their non-halophilic counterparts. An important finding, however, is that the archaeal proteins involved in these processes do not represent a reduce repertoire of eukaryotic proteins but are rather a mosaic of eukaryal and bacterial systems with archaeal-specific features.