Consistent with previous findings (Kim and Li, 2004), we found that flp-20 is expressed in the TRNs (ALM, AVM, PLM, PVM), along with a few other neurons (ASE, LUA, and PVC).
Staining was first detected in young L1 larva in 23 nuclei that have morphology typical of hypodermal cells. These 23 nuclei correspond to hyp-7. No staining was detected in Pn.p cells that do not fuse with hyp7. hyp6 was also detected later in development. hyp6 nuclei are consistently stained in adult, occasionally observed as early as L3.
Expression begins in early embryos and continues into young larval stages. In older embryos and young larvae extensive nuclear expression is seen in hypodermal cells. In young embryos mosaic nuclear-localised and diffuse expression is seen in a variable number of cells (from a few to most cells in the embryo).
Expression is confined to embryos and young larvae. In elongated embryos and young larvae diffuse expression is seen within the intestine. In pre-comma stage embryos a few nuclei (possibly intestinal precursors) show expression.