Intact piRNA pathway prevents L1 mobilization in male meiosis
Résumé
Significance Retrotransposons make up the bulk of the human genome and, if unleashed, threaten the genomic integrity through DNA damage and insertional mutagenesis. In germ cells, an intact PIWI-interacting RNA pathway is essential for suppressing the expression of L1 retrotransposons. Deficiencies in the PIWI-interacting RNA pathway have dire consequences because mutant males are invariably sterile. To address the role of retrotransposon activation in these mutants, we developed an L1 reporter transgenic mouse. This mouse model allowed us to detect significant and stage-specific increases of new insertions in mutant germ cells, to draw attention to the importance of other L1-related activities for germ-cell health, and to predict the timing and origin of heritable L1 insertions in the human population.