zuIs60 [pie-1p::GFP(secreted) + unc-119(+)]. Maternally-expressed secreted GFP fills spaces between embryonic cells, and space between embryo and vitelline membrane. Useful marker for vizualizing intercellular spaces in embryos. Reference: Wehman AM, et al. Curr Biol. 2011 Dec 6;21(23):1951-9.