::gfp reporter gene containing a 4.2-kb acr-5
promoter fragment is expressed exclusively in the nervous system. Expression is initiated in the embryo and persists throughout adult life. In the ventral nerve cord of L1 larvae, acr-5
::GFP expression is restricted to the embryonically derived DB motor neurons. VB motor neurons, which arise during the late L1 stage, begin to express acr-5
::GFP in L2 larvae. acr-5
::GFP is also expressed in other unidentified neurons in the head and tail.