Repression of the Heat Shock Response Is a Programmed Event at the Onset of Reproduction

Abstract

The heat shock response (HSR) is essential for proteostasis and cellular health. In metazoans, agingisassociated with a decline in quality control, thusincreasing the risk for protein conformational disease. Here, we show that in C.elegans, the HSR declines precipitously over a 4hr period in early adulthood coincident with the onset of reproductive maturity. Repression of the HSR occurs due to an increase in H3K27me3 marks at stress gene loci, the timing of which is determined by reduced expression of the H3K27 demethylase jmjd-3.1. This results in a repressed chromatin state that interferes with HSF-1 binding and suppresses transcription initiation in response to stress. The removal of germline stem cells preserves jmjd-3.1 expression, suppresses the accumulation of H3K27me3 at stress gene loci, and maintains the HSR. These findings suggest that competing requirements of the germline and soma dictate organismal stress resistance as animals begin reproduction.