Figure 7.

Slit2 enhances trunk neural crest motility in a wound assay. Trunk neural tubes were cultured overnight on fibronectin. After one day, media was changed to one conditioned by control or Slit2-secreting cells. A wound of one to two cells width was made with a fine pipette. After 2 h, the percent of wounds with cells crossing and sealing the gap was determined. (a, unsealed) Image of a neural crest culture fixed immediately after wounding and stained with the HNK-1 antibody. (a, sealed) Image of a similar culture fixed 4 h after wounding showing that many neural crest cells have sealed the gap by this time point. (b) Primed neural crest cultures were incubated for 2 h before performing the wound with media conditioned for 5 d by control HEK cells or Slit2-secreting cells. Nonprimed corresponds to neural crest cells that were not preexposed to Slit2 in the media before the wound. Data correspond to one representative experiment out of eight. (c) Slit2 enhances wound healing of trunk, not vagal, neural crest, and this effect can be reversed by soluble Robo. The enhanced migration of trunk neural crest by Slit2 was significantly reduced by the presence of RoboN in the media. Neural crest cultures were primed for 2 h before performing the wound with media conditioned for 5 d by control HEK cells, Slit2-secreting cells, or a 1:1 combination of RoboN and Slit2 media. After 2 h of culture, the percent of wounds with cells crossing and sealing the gap was determined. Data correspond to one representative experiment of six.