Fig. 3

Expression of tbx-20/mab-9 in C. elegans. (A) L1 larva containing the genomic rescuing mab-9::GFP reporter pAW118 (Woollard and Hodgkin, 2000). Nuclear MAB-9 expression is detected in all embryonically-derived motor neurons (DA, DB and DD). Expression is also observed in a head neuron (out of focal plane), B and F rectal epithelial cells and posterior hypodermal cells of the tail, as previously reported (Woollard and Hodgkin, 2000). (B) Expression of mab-9::GFP is detected in post-embryonically derived AS and VD motor neurons in addition to embryonically derived DA, DB and DD motor neurons. No mab-9::GFP expression is observed in VA and VB motor neurons. C: mab-9::GFP expression in the head region of an animal also expressing ceh-10::GFP (which is only expressed in RID and not ALA in this particular integrant (lqIs4); Oliver Hobert, pers. comm.). Two nuclei are clearly visible (labelled RID and ALA), with MAB-9 in a nucleus just posterior to RID. This confirms its identity as ALA. Dorsal is up, posterior to the right in all panels.