Fig. S1

Qualitative and quantitative analysis of cell migration in Ptges-deficient embryos during gastrulation. (A) Schematic of PGE₂ synthesis. Blue star, location of pathway inhibition by MO. COX, Cyclooxygenase-/Prostaglandin-endoperoxide synthase type 1 and 2; PGG₂, Prostaglandin G₂; PGH₂, Prostaglandin H₂; PGE₂, Prostaglandin E₂; MO, antisense morpholino oligonucleotide; Ptges, Prostaglandin E synthase; EP4, E-prostanoid 4 receptor. (B,C) Schematic of gastrulation movements in zebrafish at the shield (B) and tailbud (C) stages. (D,E) Protrusive activity of axial mesodermal cells undergoing epiboly (yolk cell-embryonic cell margin) in control (D) and tailbud (E) embryos. Arrowhead, blebbing activity. (F) The net speed (µm/minute) of superficial and deep mesendodermal cells in control embryos and ptges morphants. **, P<1×10^-4. (G) Quantitation of the length changes (µm/15 seconds) of four prechordal mesoderm cell protrusions per sample during the time-lapse. Cellular protrusions from ptges morphants show less extension and retraction than those from control embryos (*, P=0.03). Red line, average protrusion length. (H,I) Protrusion length in prechordal mesoderm cells migrating anteriorly towards the animal pole. Four protrusions (embryo 1, solid lines; embryo 2, dashed lines) were analyzed in control (red) and ptges (blue) morphant gastrulae at 60-75% (H) and 80-90% (I) epiboly during time-lapse imaging. Control morphant protrusions are filopodia (length>width; diameter<2 μm), whereas ptges morphant protrusions exhibit lamellipodial (width>length; length>2 μm) or bleb-like characteristics (Montero et al., 2003).