Abnormal 3' junctions of the MLV provirus in Mre11-deficient cells. (A) Junctions were analyzed in Mre11-deficient cells and Mre11-complemented cells transduced with the MLV-based vector. Abnormal nucleotides corresponding to dinucleotides (TT) processed by integrase are in bold. Underlined sequences indicate partial PBSs. Squares indicate the location of micro-homologies to TT dinucleotides and/or the PBS. (B) The number of junctions with insertions or deletions. The P values under the table are for comparison of the number of junctions with insertions in Mre11-deficient cells to that of Mre11-complemented cells.