Fig. 4. smedbmp4-1 signaling is required for blastema patterning. White lines indicate approximate boundary between pre-existing tissues and blastema. The diagram on the left shows the sites of amputations (black lines); data for trunks regenerating new heads are shown. Anterior, left. (A) Animals were labeled with an antibody that recognizes cilia (anti-acetylated tubulin). White arrows indicate aberrant cilia patterning at the midline of cephalic blastemas. The dorsal surface is shown. Animals had between 7 and 9 days of regeneration. Scale bars: 0.1mm. (B) Animals were labeled with antibodies that recognize the photoreceptor neurons (VC-1, anti-Arrestin) and the cephalic ganglia (SYT, anti-Synaptotagmin). Animals had between 7 and 8 days of regeneration. P, photoreceptors. Arrows indicate midline of cephalic ganglia and optic chiasmata.