Establishment of a Cre-loxP System Based on a Leaky Promoter and an Unstable panARS Element in .

The Cre-loxP system produces structural variations, such as deletion, duplication, inversion and translocation, at specific loci and induces chromosomal rearrangements in the genome. To achieve chromosomal rearrangements in , the positions and sequences of centromeres were identified in this species for the first time. Next, a Cre-loxP system was established in . In this system, the Cre recombinase was expressed from a leaky promoter in a plasmid to alleviate the cytotoxicity of Cre, and the unstable plasmid contained a panARS element to facilitate the clearance of the plasmid from the cells. By using as a reporter gene, the recombination frequencies between loxP sites or loxPsym sites were 99% and 73%, respectively. A strain containing 16 loxPsym sites in the genome was constructed. The recombination frequency of large-scale chromosomal rearrangements between 16 loxPsym sites was up to 38.9%. Our study provides valuable information and tools for studying chromosomal structures and functions in .