Fig. S2

Effect of DAPT on neuromast orientation. (A) A low-magnification image shows one neuromast deposited by the first primordium (arrow) and two neuromasts produced by the second primordium (double arrows). Note the more ventral position of the latter neuromasts. Interneuromast cells of the first primordium displaced by the ventrally migrating neuromasts of the second primordium are marked with arrowheads. (B) A neuromast deposited by the second primordium displays a dorsoventral orientation. (C) A low-magnification image depicts neuromasts derived from the first (arrow) and second (double arrow) primordia in the posterior lateral line of a cldnB:lynGFP larva treated with 100 μM DAPT. The ventral migration of the second neuromast displaces a trail of interneuromast cells left by the first primordium (arrowhead). This indicates that positioning of the second primordium-derived neuromast relative to the anteroposterior and dorsoventral axes is not affected by DAPT treatment. (D) At a higher magnification, the neuromast derived from the second primordium displays hair cells oriented primarily along the anteroposterior axis and showing an anterior bias (inset). (E) In another preparation, the corresponding neuromast contains obliquely oriented hair cells and displays a posterodorsal bias (inset).