Fig. 7.

Co-localization of neural marker gene expression with ectodermal sensory neurons (ESNs) in amphioxus larvae. All animals are shown in lateral view with their anterior end directed towards the right. a, a′ hu/elav, b, b′ tlx, and c, c′ soxb1c gene expression (yellow) was detected in amphioxus larvae at 36 hpf (hours post fertilization). ESNs were labeled by immunostaining against glutamate (GLU-ir, green) and acetylated tubulin (AT-ir, red). Nuclei were labeled with the nucleic acid dye Hoechst (blue). The white boxes in a–c indicate the position of the respective close-ups shown in a′–c′. Close-ups were generated from confocal z-stacks that only include the lateral ectoderm on one side of the larvae. Arrows in a′ indicate differentiated ESNs expressing hu/elav and the arrowhead an undifferentiated ESN progenitor (ESNP) expressing hu/elav. The arrow in b′ highlights a differentiated ESN expressing tlx and the arrowhead a differentiated ESN that does not express tlx. Arrows in c′ mark differentiated ESNs that do not express soxb1c and the arrowheads undifferentiated ESNPs expressing soxb1c. The scale bar in a also applies to b, c, and the scale bar in a′ also applies to b′, c′