Sperm-specific mechanism that induces the gross chromosomal rearrangements

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Gross chromosomal rearrangements(GCRs) are often generated by illegitimate repair between two DNA breakages at regions with nucleotide sequences that potentially adopt a non-B DNA structure. We previously established a plasmid-based model system that recapitulates palindrome-mediated recurrent translocations in humans, and demonstrated that cruciform DNA is required for the rearrangements. In this study, we show that two sequential reactions that cleave the cruciform structures induce the translocation : GEN1-mediated resolution that cleaves diagonally at the four-way junction of the cruciform, and Artemis-mediated opening of the subsequently formed hairpin ends. These two intrinsic pathways that normally fulfill vital functions independently, Holliday junction resolution in homologous recombination and coding joint formation in rearrangement of antigen-receptor genes, act upon the unusual DNA conformation in concert and lead to these recurrent GCRs in humans.