Light-controlled Spo11-less meiotic DNA breaks by MagTAQing lead to chromosomal aberrations.

TAQing technologies are based on the restriction enzyme-induced DNA double-strand break (DSB) formation in living cells, which results in large-scale genomic rearrangements and phenotypic alterations. Originally, the TAQing system requires heat treatments to activate restriction enzymes, which sometimes leads to cell toxicity or stress responses. Here, we developed a blue-light-controlled MagTAQing system, which induces DSBs exclusively upon blue-light exposure by assembling the split restriction enzymes via Magnet modules. Application of MagTAQing to mitotic budding yeast cells successfully triggered various genomic rearrangements upon blue-light exposure. Since this technology enables the conditional induction of genomic rearrangements in specific cells or tissues, we employed MagTAQing on meiotic yeast cells lacking the recombinase Spo11 to induce artificial DSBs. Consequently, Spo11-independent meiotic DSBs resulted in aneuploidies and nonallelic homologous recombinations between repetitive sequences such as ribosomal DNA and retrotransposons. These results suggest a pivotal role of Spo11-induced recombination in preventing chromosomal abnormality.