Search for DNA repair pathways in Drosophila melanogaster

The knowledge about the existence of different pathways for the repairing of DNA lesions has made possible a better understanding of mutation processes. The double mutant method has been shown to be useful for grouping rad mutants in yeast. Through this method, three different groups of repair mechanisms were found: (a) RAD3 group corresponding to the excision repair of UV lesions, (b) RAD6 group corresponding to the translesion type of post-replication repair and (c) RAD52 group corresponding to the recombination type of post-replication repair. In this work, a search for a classification of Drosophila mus mutants in groups analogous to yeast RAD groups is done. Information obtained by double mutant studies was integrated with that obtained by biochemical, recombination, DNA damaging agent sensitivity and mutation studies. The following groups were found: (a) group of mei9 and mus201, analogous to RAD3, (b) group of mei41 and mus302 analogous to RAD52 and, (c) group of mus104 and mus101 analogous to RAD6. In addition, there are mutants that belong to a group corresponding to pre-replication repair of MMS lesions such as mus103, mus306 and mus207. As a peculiarity of Drosophila, it was found that interaction between pre- and post-replication repair mechanisms is indifferent and not synergistic as was found in yeast. A possible explanation could be a weaker control of post-replication repair mechanisms in Drosophila than in yeast. It is expected that this research could help for a better understanding of repair mechanisms in complex organisms.