CONSERVATION OF EUKARYOTIC DNA-REPAIR MECHANISMS

Purpose: To discuss the evolutionary conservation of different DNA rep air processes. Summary: The proteins that carry out base excision repa ir show a varying degree of structural conservation, but a high level of functional complementation between species, as might be expected fo r a sequential pathway. In nucleotide excision repair there is a high degree of structural conservation, but Few examples of functional comp lementation because the process involves multiprotein complexes. Repai r by homologous recombination involves proteins that are highly conser ved structurally. The process of repair of DNA breaks by non-homologou s end-joining is conserved in eukaryotes, but the level of sequence id entity of several of the proteins is fairly low and some components in volved in man do not appear to have sequence homologues in yeast. Conc lusions: All DNA repair processes are highly conserved. The degree of structural and functional conservation varies between the different pr ocesses.