Effects of varying gene targeting parameters on processing of recombination intermediates by ERCC1-XPF.

The ERCC1-XPF structure-specific endonuclease is necessary for correct processing of homologous recombination intermediates requiring the removal of end-blocking nonhomologies. We previously showed that targeting the endogenous CHO APRT locus with plasmids designed to generate such intermediates revealed defective recombination phenotypes in ERCC1 deficient cells, including suppression of targeted insertion and vector correction recombinants and the generation of a novel class of aberrant recombinants through a deletogenic mechanism. In the present study, we examined some of the mechanistic features of ERCC1-XPF in processing recombination intermediates by varying gene targeting parameters.