Fig. 3. Effect of BMP2 concentration on differentiation of BRN3A⁺ and PHOX2B⁺ cells in dNT cultures. Cultures grown for 4 days in the indicated concentrations of BMP2 were fixed and double-labeled with anti-BRN3A (A,D) and anti-PHOX2B (B,E). (G) The number of BRN3A⁺ or PHOX2B⁺ cells/cm² was measured in a standard cloning ring. Numbers indicate the mean±s.e.m. of two independent experiments with quadruplicate dishes in each experiment. *The number of BRN3A⁺ cells is significantly different (P<0.01) from the number of PHOX2B⁺ cells at the indicated dose of BMP2.