Fig. 2

Divergent expression of PC1/3 and PC2 in Tribolium. Stages according to [28], NS14 is the last germband stage in which the legs reach the anterior tips of the posteriorly following segment after the next, stage 15 is the last embryonic stage before hatching when the whole embryo is of an oval shape. A NBT/B-ZIP colorimetric stain of embryonic PC2 expression, showing the anterior half of an embryo of stage NS14. The signal is located to the ventral neuroectoderm (arrowheads) and prospective brain area (arrow). B Fluorescent in situ stain of an embryo at stage NS15. PC2 expressing cells (red) are associated with the developing central nervous system in the ventral neuroectoderm (arrowheads) and the prospective brain (arrow). Note that not all neurons are visible in this projection: the anterior brain commissures are already present but are located on a deeper level. The strong staining in the first abdominal segment (seen in A and B, asterisks) represents unspecific signal from the pleuropods. C Ubiquitous PC2 expression in the anterior larval nervous system. Shown is the brain and suboesophageal ganglion (SOG). Cell bodies and nuclei are located in the periphery and project their axons into the central neuropile (visualised by anti-synapsin). Some more intense staining is visible in the anterior medial brain (arrow). D PC1/3 expression in the larval nervous system is restricted to individual cells of the dorsal side of the suboesophageal ganglion (arrows) and the posterior brain (arrowheads). Those cells are present bilaterally, but signal is obscured on the left side by unspecific signal of trachea (encircled areas). B/C/D are maximum intensity Z-projections (created with imageJ) and are based on multichannel confocal laser scanning image stacks with each channel using the same plane thickness to avoid optical shift