Fig. 5. Effects of Alx1 MOs in S. purpuratus (A-H) and L. variegatus (I-N). MO-injected embryos were examined 36 hours (B,D,F,H) or 54 hours (J,L,N) postfertilization. (A-F) In situ hybridizations with SpMSP130-related 2, SpP19 and SpFRP probes. Control embryos show strong signal in large micromere progeny in the vegetal plate and in PMCs following ingression (A,C,E, arrows) (see also Illies et al., 2002). MO-injected embryos show few or no positive cells. (G,H) Immunostaining with mAb 6a9, showing stained cells (PMCs) in control (G, arrow) but not MO-injected (H) embryos. (I,J) Endo1 expression in the midgut of a control pluteus at 24 hours (note that the hindgut is out of focus) and in the midgut/hindgut of a MO-injected embryo. (K,L) Myosin heavy chain expression in circumesophageal muscle cells (arrows) of a control pluteus (24 hours) and in a MO-injected embryo. (M,N) Pigment cells in the aboral ectoderm of a control (arrow; 48 hours) and a MO-injected embryo.