Bridge-induced translocation (BIT) by targeted DNA integration in yeast.
Valentina Tosato, Carlo V. Bruschi
Microbiology Laboratory, ICGEB, AREA, Padriciano 99, Trieste, I-34012, Italy
Experimental systems exist, which are able to generate only specific reciprocal translocations between engineered chromosomal loci of yeast and Drosophila, but not in wild-type cells. Here we report the successfull induction of chromosome translocations in the yeast Saccharomyces cerevisiae by targeted DNA integration of the KAN R selectable marker, flanked by two DNA sequences homologous to two different chromosomes. Using this Bridge-Induced Translocation (BIT) system, from 2 to 4% of all integrants, depending on the length of the homologous DNA ends, showed targeted non-reciprocal translocations between chromosomes V-VIII and VIII-XV in two wild-type strains. The complex fate of the chromosomal fragments generated indicated the involvement of multiple repair pathways in a two-step integration dynamics. The possibility of inducing chromosomal translocations between any two desired genetic loci in a eukaryotic model system will be instrumental for their molecular characterization, as well as for the understanding of the genesis of Gross Chromosomal Rearrangements.