Fig. 6. Xenopus DFC-like cells and Ca2+ requirement for
laterality. Xenopus embryos incubated with Syto-11 at stage 11.5
and sagittally bisected at (A) stage 14 and (B) stage 17 showing
Syto-11-labeled cells enriched in the future tail region. (C) Stage 17
archenteron roof explant, showing Syto-11 staining of the node (arrow) and
surrounding LPM. (D) Explant in C immunostained for acetylated tubulin
(acTub), which is enriched in the node region (arrow). (E) Ventral view
of stage 46 control-treated embryo, showing situs solitus, or normal
lateral asymmetry. The heart is outlined, showing the left-sided position of
the ventricle and right-sided outflow tract. The gut coils counterclockwise,
as shown by the arrow. (F) Ventral view of a thapsigargin-treated
embryo at stage 46, showing an example of situs inversus, or reversed
laterality. The heart is outlined, showing the right-sided position of the
ventricle and left-sided outflow tract. The gut coils clockwise, as shown by
the arrow. (G) Left-sided xnr1 expression at stage 22-24 in a
DMSO-treated embryo. (H) Bilateral xnr1 expression in a
thapsigargin-treated embryo. (I,J) Lateral view of
β-catenin protein localization in control-treated (I) and
thapsigargin-treated (J) stage 13 embryos. Note increased number and intensity
of nuclear staining. (K,L) Lateral views of control (K) and
thapsigargin-treated (L) embryos, showing normal axial development. (M)
Summary of Xenopus laterality data. Thap, thapsigargin.