Targeting construct for ends-out homologous targeting of mre11. Contains two fragments that normally flank the mre11 gene. The upstream homologous fragment is a 2.5kb fragment from immediately upstream of the mre11 start codon. This is followed by the Avic\GFParm.PG marker. The downstream homologous fragment is a 2.9kb fragment from downstream of the mre11 gene. A RS(I-SceI) restriction site is present upstream of the upstream homologous fragment.