Single nuclei stained with DAPI (cyan) and recombinase RAD-51 (red). In top-3 mutant RAD-51 foci were much more abundant and coalesced into stretches, which is never observed in the wt. (c) Taken from Figure 1 Dello Stritto et al., JCB 2021.
During germ cell development faulty meiocytes are eliminated via apoptosis, a programmed cell death to ensure that only healthy gametes are produced. The lab of Verena Jantsch has now discovered a previously undescribed role for topoisomerase 3 (TOP-3) in oocyte quality control of the model organism C. elegans. In the absence of TOP-3, cells accumulate aberrant recombination intermediates in the pre-meiotic and meiotic compartments of the gonad that are less capable of triggering apoptosis. DNA repair is directed to less accurate pathways, resulting in a pool of oocytes with low quality. The study is published in the Journal of Cell Biology.