Figure 6.

Expression patterns of Pdu-Hes1 and their schematic representations in Platynereis larvae and during posterior elongation (PE). Whole-mount in situ hybridizations (WMISH) for the different stages indicated on each panel are shown. Pdu-Hes1 is first expressed in ectodermal columns at 24 h post fertilization (hpf) then restricted to the midline and segment epidermis lateral cells that form a more or less continuous line in each segment at 48 and 72 hpf. During PE, Pdu-Hes1 is still expressed in the midline and the whole segment epidermis, (while more intensively at the segment boundaries and borders), but also in the ectodermal segment addition zone (SAZ) and at the basis of the anal cirri. In the dorsal part, its expression is in the form of broad stripes but some distance away from the SAZ, therefore in maturing segments. For the larvae, panels are ventral views (anterior is up). Expressions patterns during PE are shown for both sides (anterior is up), V = ventral, D = dorsal.