Fig. 2

Defects in cell movements in maternally mutant mis embryos. (A–E) Defect in cell mixing during early epiboly. (A) Labeling strategy, by uncaging fluorescent tracer at the sphere stage. Uncaging of a group of cells at the sphere stage in wild-type (B) and mis mutant (C) embryos is followed by extensive cell mixing in the wild-type (D) but little mixing in the mutant (E). (B–E) are side views, tilted toward the animal pole. Time after fertilization as indicated in h:min. Uncaging was carried out at 4:30 h.p.f., and some cell mixing has already occurred in (B,C). Embryos shown in (A–E) are representative of 5 wild-type and 5 mutant embryos. (F–X) Cell autonomy of movement defect. (F) Labeling strategy, by co-transplantation of rhodamine-labeled cells from wild-type (red) and fluorescein-labeled cells from maternally mutant mis (green) donors at the sphere stage (4 h.p.f.) into isochronic unlabeled wild-type host embryos. (G–L) Wild-type cells visualized with the rhodamine channel. (M–R) Mutant cells visualized with the fluorescein channel. (S–X) Merged images. Chimeric embryos were monitored for the first 24 h of development, and a subset of time points is shown (h:min p.f., indicated in (S–X)). Wild-type cells populate the embryonic axis of the host, while mutant cells remain in regions overlying the yolk cell. The embryo shown in (G–X) is representative of transplantations into 30 donor embryos. All panels are lateral views with dorsal to the right, except (L,R,X) with dorsal at the top and anterior to the left.