Fig. 2.

Spib morpholino affects myeloid cell production but not cardiac specification. (A–D) Tailbud stage 23 embryos injected with the Xtspib-e1i1MO into dorsal blastomeres (A–D), 40 ng dose, or as a control in ventral blastomeres (E and F), or non-injected sibling (G and H). Embryos subjected to wholemount in situ hybridization for mpo (myeloid/macrophage) and nkx2-5 (heart field). Dorsal-injected embryos exhibited either a severe loss of the myeloid domain (A and B) or a milder reduction (C and D). Nkx2-5 mRNA expression detected in all examples. (I–P) Late tailbud stage 28 embryos injected with the spib morpholino, 40 ng dose and with the same sequence of blastomere injections presented. Embryos hybridized with probes for mpo and tbx5. Cardiac tbx5 mRNA detected in all examples. Anterior is to left, lateral views and ventral view of heart fields.