Capture of a recombination activating sequence from mammalian cells.

Abstract

We have developed a genetic trap for identifying sequences that promote homologous DNA recombination. The trap employs a retroviral vector that normally disables itself after one round of replication. Insertion of defined DNA sequences into the vector induced the repair of a 300 base pair deletion, which restored its ability to replicate. Tests of random sequence libraries made in the vector revealed a putative recombination signal (CCCACCC). When this heptamer or an abbreviated form (CCCACC) were reinserted into the vector, they stimulated vector repair and other DNA rearrangements. Mutant forms of these oligomers (eg CCCAACC or CCWACWS) did not. Our data suggest that the recombination events occurred within 48 h after transfection.