Morpholinos targeting conserved and cnidarian-specific transcripts disrupt development.

<p>DIC imaged larvae developed from morpholino-injected eggs after 24hpf and 48hpf development or at the early gastrula stage as indicated. Typical morphology observed at non-toxic morpholino doses are shown in each case, with the oral pole at the top. Similar phenotypes were obtained using a second morpholino in all cases, except FoxQ2c and WegA1, for which no second non-toxic morpholino could be designed. Uninjected embryos (A) and control-MO injected embryos (L) had completed gastrulation at 24hpf with endodermal epithelialisation starting at the aboral pole. By 48hpf uninjected planula larvae (G, Q) had formed with endodermal epithelial layers (black arrows) organized around a central stripe-like cavity and a well-defined lamina layer separating the endoderm and ectoderm (green arrows). WegO1-MO1 embryos showed minor disruption of gastrulation with embryo elongation slightly compromised at 24hpf (B) and the oral half, thin and tapered (asterisk) at 48hpf (H). Morpholinos targeting either Bra1(C, I) or Bra2 (D, J) showed severe delays in gastrulation. By 48 hpf some embryo elongation had occurred but the blastocoel contained only loose, disorganized material. WegA1-MO embryos (F) showed massive cell ingression at the onset of gastrulation, when cell ingression had barely initiated in uninjected embryos cultured in parallel (E). At 48 hpf (K) the endoderm was enlarged and the ectoderm layer was very thin and irregular (black arrowhead). FoxQ2c-MO (M, R) and WegIE2-MO (N, S), showed severely reduced endodermal layer at 48hpf. WegD1-MO and HD02-MO embryos showed severe defects in overall morphology (O, P, T, U), lacking a well defined basal lamina between endoderm and ectoderm. Green arrows indicate the position of this interface. Black arrows indicate the endodermal epithelial layers in G, Q, R and S. Red arrows indicate ingressing cells at the onset of gastrulation in C, D, E and F. Scale bar 50 µm for all panels.