Fig. 6 . Effects of Mi-2ß depletion on the signaling network that controls hair follicle morphogenesis. (A-D) Immunofluorescence of E18.5 dorsal skin labeled with antibodies against Edar or Edar and E-cadherin (A), or against Mi-2ß and Edar (B,C), or against Mi-2ß and E-cadherin (D). (C,D) In situ hybridization of E18.5 dorsal skin with probes against Shh and Wnt5a. The depletion of Mi-2ß in follicles was confirmed by immunofluoresence staining of adjacent serial sections using antibodies to Mi-2ß and E-cadherin. DAPI-stained nuclei are blue. (A,B) In the WT, a local increase in Edar expression was detected among basal epithelial cells (asterisks) that give rise to the hair placode, as well as within the hair follicle (arrowhead). Edar upregulation was followed by a decrease in E-cadherin expression (A, WT). In the mutant, no Edar upregulation or E-cadherin downregulation was seen in areas of the mutant skin in which Mi-2ß was absent (A, mutant). By contrast, in areas with mosaic Mi-2ß depletion, follicular structures expressing Edar were detected in the Mi-2ß mosaic area in the mutant (arrowhead in B mutant, Cb). Shh expression was seen at the tip of stage-2 and stage-3a follicles in the WT (Cc and Da). In the mutant, Shh transcript was seen in stage-2 follicles with mosaic Mi-2ß depletion (Cd), but was significantly reduced in the Mi-2ß-null counterparts (Ce). By contrast, Shh was seen in Mi-2ß-null stage-3a follicles (Db). Expression of Wnt5a was observed in the dermal condensate of stage-3a follicles in the WT and in Mi-2ß-positive stage-3a follicles in the mutant (Dc and De). Wnt5a was, however, significantly reduced in the Mi-2ß-null counterparts (Dd).