We examined a GRH-1:: GFP::3xFLAG fusion protein expressed from the endogenous
grh-1 locus. We observed the first detectable signal in elongating embryos, that is, at the time when oscillatory gene expression initiates (Meeuse et al, 2020). In larvae, GFP signal accumulated in various cell types, including seam cells, vulva precursor cells, non-seam hypodermal cells, pharyngeal cells, and head neurons. Finally, in adults, which lack oscillatory gene expression (Meeuse et al, 2020), GFP levels were diminished or altogether absent in various tissues.