Staining embryos with this anti-VAB-7 antibody confirmed that VAB-7 is expressed in posterior muscle and epidermal cells. However, a second phase of VAB-7 expression was discovered in embryonic ventral nerve cord (VNC) neurones, beginning at the 1.5-fold stage. At the threefold stage VAB-7 is expressed in nine neuronal nuclei (seven in the VNC and two nuclei in the head), and in the five most posterior epidermal nuclei, which form the
hyp8 to
hyp11 cells. VAB-7 is expressed in the seven DB class motoneurones; VAB-7 staining is also seen in two additional head neurones that have not been identified. DB neurones express VAB-7 throughout development. In addition, VAB-7 is expressed continuously in the hypodermal syncitium
hyp10, and from the L1 stage in four unidentified neurones in the tail. Finally, at the adult stage, VAB-7 is detected in three VC neurones: VC1, VC2 and VC6.