Inside the six3-free region, we detect restricted expression of several
transcription factors (using the nuclei of the two apical
tuft cells for reference; yellow circles in confocal apical
views in Figure 2): otp (Figure 2G”;inadditiontoitsring-like expression, see above), nkx3 (Figure 2Q’), foxj (Fig- ure 2K’) and hox1 (Figure 2L’).