Fig. 2

Transplantation and transgenic analysis demonstrates that ErbB2 is required within Schwann cells and Nrg1-3 within lateral line neurons to inhibit extra neuromast formation.

(A and A′) Alexa-568 dextran (red) labeled erbb2 mutant cells were transplanted into Tg(foxd3:gfp) (green) wild type fish. (A) High magnification view shows erbb2 interneuromast and mantle cells along the lateral line and around neuromasts (arrows). These erbb2 interneuromast cells fail to induce extra neuromasts by 4 dpf (A′). (B-B′′′) Alexa-568 dextran (red)/Tg(foxd3:gfp) (green) wild type cells were transplanted into erbb2 mutant host. At 4 dpf neuromast were labeled by DASPEI staining (green). (B and B′) On the untransplanted side there are no Schwann cells and eighteen neuromasts. (B′′ and B′′′) On the transplanted side you can see complete migration of wild type Schwann cells in an otherwise erbb2 mutant fish and rescue of neuromast number (arrows). (C and D) Dominant negative ErbB receptor expression in neural crest derived cells mimics erbb mutant phenotype. (C) Control Tg(SqET20:gfp) siblings at 4 dpf. (D) Tg(SqET20:gfp)/Tg(sox10:DNerbb4) showing extra neuromasts. (E-E′′′) Alexa-568 dextran (red)/Tg(clndB:lyngfp)(green) wild type cells were transplanted into nrg1-3^z26 mutant host. (E-E′) At 4 dpf the untransplanted side has nineteen neuromasts. (E′′ and E′′′) On the transplanted side there are GFP labeled axons (arrowhead) along the entire length of the lateral line with rescue of neuromast number. All axons cannot be seen because some are obscured underneath pigment cells.