The expression pattern of lhIs35[Punc::55::gfp] was similar to previous observations (Zhou and Walthall, 1998) except that VD precursor cells were also labeled. GFP was detected in the 13 VD neurons, 11 AS neurons, VA1 and PDB. Punc-55 activity was highest during L2, and was not detected beyond L4, as reported (Zhou and Walthall, 1998).
At the time when the Q descendants are beginning their migrations in early L1 larvae 4-4.5 hours post-hatching, Pspon-1::gfp expression was observed in posterior body wall muscles cells, but not in the Q cells as determined by the Q-cell specific marker rdvIs1 (Pegl-17::mCherry) (Branda and Stern, 2000; Ou et al., 2010). Pspon- 1::gfp expression was in body wall muscle cells adjacent to the Q neuroblasts, with expression extending posteriorly to the tail, but only a short distance anteriorly.
In support of a role of ARX-2 in Q cell corpse clearance, ARX-2::GFP was recruited onto Q cell corpses at 37 ± 9 min (mean ± SD; n = 20) after Q cell birth, and the ARX-2::GFP rings lasted for 19 ± 9 min (n = 20). The corpse was completely degraded 34 ± 18 min (n = 20) after the disappearance of ARX-2::GFP, which suggests that ARX-2 may function during the engulfment of Q cell corpses but may not be involved in the final degradation inside the phagosome.
COR-1::GFP is enriched at the leading edge of the Q cell. Quantitative fluorescence analysis showed that the COR-1::GFP intensity was 1.7-fold as strong in the leading edge of migrating Q cells as in the lagging edge.