Abstract
Distinguishing endogenous genes from selfish ones is essential for germline integrity. In animals, small regulatory RNAs play a central role in this process; however, the underlying principles are largely unknown. To fill this gap, we studied how selfish toxin-antidote elements (TAs) evade silencing in the nematode Caenorhabditis tropicalis. We found that the slow-1/grow-1 TA is active only when maternally inherited. Surprisingly, this parent-of-origin effect stems from a regulatory role of the toxin’s mRNA: maternal slow-1 mRNA—but not SLOW-1 protein—licenses slow-1 expression in the zygote by counteracting piRNAs. Our results indicate that epigenetic licensing—known to play a role in C. elegans sex-determination—is likely a common mechanism that hinders the spread of selfish genes in wild populations while ensuring a lasting memory of self in the germline.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
↵* These authors jointly supervised this work
