Description

wrt-2 encodes a hedgehog-like protein that is weakly required for molting (Kouns et al., 2011). As monitored using a transcriptional GFP reporter, wrt-2 is expressed in seam and hypodermal cells throughout development (Apock et al., 1999). However, wrt-2 transcript levels oscillate with a period consistent with the timing of the molting cycle (Hendriks et al., 2014). Because standard GFP reporters do not capture rapid changes in gene expression, we generated a wrt-2 transcriptional reporter driving expression of a rapidly degraded GFP (GFP-pest) to observe the precise timing of wrt-2 expression throughout development. Consistent with previous findings, Pwrt-2::GFP-pest expression was observed in hypodermal and seam cells at all larval stages. However, expression was not constant throughout development but rather cycled on and off at each larval stage (Figure 1 B and C). Pwrt-2::GFP-pest expression was first observed in the embryo and turned off at hatching (Figure 1A). Expression ceases at the end of L4 and no expression was observed in adult animals. We confirm that wrt-2 expression oscillates with the molting cycle and demonstrate that these oscillations are driven by the 5’ regulatory region of wrt-2.