Fig. 4.

Electroporation of pCaβGFP confirms the extensive movement of the occipital lateral mesoderm. The lateral mesoderm next to somites 1-2 (A–E, lm1+lm2) or somite 1 (F, lm1) was electroporated with pCaβGFP at HH10. At the time points indicated on top of the panel, the electroporated cells were traced based on the fluorescence of GFP (A–E) or GFP mRNA expression (F, blue staining). Dorsal (A) or lateral (B–F) views, rostral to the top; (Bi, ii) are higher magnifications of labelled cells at HH16, Bii corresponds to the specimen shown in (B). Note that the lateral mesodermal cells derived from somite levels 1 and 2 organised themselves into two streams, one extending along the floor of the pharyngeal arches towards the mandibular arch and the outflow tract of the heart, the other one extending laterally. Abbreviations: ht, heart; ma, mandibular arch; oft, outflow tract of the heart; and ov, otic vesicle.