| Type | MGI:General | Description | at P5.5, mice show significantly fewer pigmented or LacZ+ hair follicles than control mice; also, completely undifferentiated hair follicles that are neither pigmented nor LacZ+ are observed, unlike in control mice at P5.5, the total number of melanocytes (S100b+) per hair follicle is reduced by 40% relative to that in control mice at P5.5, mice exhibit formation of undifferentiated melanocytes in the bulge area of hair follicles, along with loss of MITF (the master regulator of melanocyte development) and upregulation of ZEB1 expression the number of MITF+ melanocytes is strongly reduced relative to the total number of melanocytes per hair follicle (S100b+ melanocytes), whereas the number of PAX3+ melanocytes is normal; also, MITF protein levels are reduced in MITF+ cells most hair follicles are negative for terminal melanocyte differentiation markers, such as TYRP1 and tyrosinase enzymatic activity mRNA expression of several melanocyte differentiation markers (Tyrp1,Tyr, Dct, Pmel, Mc1R and Mitf) is significantly down-regulated in skin at E15.5 |
