Das, S. et al.
The mechanisms by which maternal stress alters offspring phenotypes remain poorly understood. Here we report that the heat shock transcription factor HSF-1, activated in the C. elegans maternal germline upon stress, epigenetically programs the insulin-like receptor daf-2 by increasing repressive H3K9me2 levels throughout the daf-2 gene. This increase occurs by the recruitment of the C. elegans SETDB1 homolog MET-2 by HSF-1. Increased H3K9me2 levels at daf-2 persist in offspring to downregulate daf-2, activate the C. elegans FOXO ortholog DAF-16 and enhance offspring stress resilience. Thus, HSF-1 activity in the mother promotes the early life programming of the insulin/IGF-1 signaling (IIS) pathway and determines the strategy of stress resilience in progeny.