A novel prokaryotic MMR pathway

Comunicación presentada en el XIV Symposium on Bioinformatics, celebrado en Granada (España) del 14 al 16 de noviembre de 2018.NucS is an endonuclease firstly identified in Archaea involved in Mismatch repair (MMR) with no structural homology to known MMR factors. By genetic screenings we report [1] that this protein is required for mutation avoidance and anti-recombination, hallmarks of the canonical MMR in the surrogate model Mycobacterium smegmatis, lacking classical MutS¿MutL factors. Furthermore, phenotypic analysis of naturally occurring polymorphic NucS in a M. smegmatis surrogate model, suggests the existence of M. tuberculosis mutator strains. Computational and evolutionary studies of NucS indicate a complex evolutionary emergence based in distinct protein domain fusions followed by at least two horizontal gene transfers leading to a disperse distribution pattern in prokaryotes. Together, these findings indicate that distinct pathways for MMR have evolved at least twice in nature.The analyses of these findings in the evolutionary context of the classical MMR proteins open novel and intriguing questions in the emergence of the MMR systems