Abnormal 5' junctions of the HIV-1 provirus in DSB repair enzyme deficient cells. (A) Junctions between the 5' end of the provirus and the host DNA were analyzed in control and mutant cell lines transduced with the HIV-based vector. Inserted abnormal sequences are in lower case. Abnormal nucleotides corresponding to the sequence (AC) complementary to the GT dinucleotides processed by integrase are presented in bold. Partial polypurine tract (PPT) sequences are underlined. Squares indicate the location of micro-homologies to the AC dinucleotides and/or PPT. (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 each cell line to that of the control MRC5SV cells.