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Figure S3. Effects of Xdsh-MA on Convergent
Extension
(A) Dorsal view of control embryo at stage 24.
(B) Control embryo at stage 10.5, hybridized
to the Xnot probe (dorsal is up).
(C) Control embryo (stage 24), hybridized to
the xSHH probe.
(D) Dorsal view of Xdsh-MA-injected embryo
at stage 24; note the reduced axis elongation
and open neural tube.
(E) Xdsh-MA-injected embryo at stage 10.5;
expression of Xnot is normal (dorsal is up).
(F) Xdsh-MA-injected embryo expression of
xSHH is normal at stage 24. It should be noted
that despite the ability of Xdsh-MA to activate
canonical Wnt signaling (see Figure 5 in the
main text), expression of the dorsal markers
Xnot and xSHH is not significantly affected
(axial-protocadherin expression was also unaffected
but was not shown). Expression of
Dvl-caax likewise activates canonical Wnt
signaling (Figure 5) but did not significantly
affect expression of dorsal markers (xSHH
and Xnot, data not shown). Both constructs
also disrupt convergent extension, but activation
of the canonical Wnt pathway is not
likely to be the cause of the convergentextension
defects because hyperactivation of
canonical Wnt signaling downstream of Dishevelled
does not inhibit convergent extension
[S12, S15]; instead, enhanced canonical
signaling likely accelerates convergent extension
by activating expression of Xnr3 [S16].
(G) Morphometrics of cells in the notochord and somites of stage-13 embryos. Plot shows length-to-width ratio (LWR) of cells plotted against
the orientation of the long axis of that cell. Control cells (red) are highly polarized; cell axes are oriented mediolaterally, and cells have high
LWR (2.06 0.087; mean SEM). Cells in Xdsh-MA-injected embryos (black) are not polarized; cell axes are randomly oriented, and cells
have low LWR (1.62 0.067; mean SEM).
(H) All cells in control embryos have their long axes oriented mediolaterally (e.g., within 45 of perpendicular to the embryonic anteroposterior
axis). Cells in embryos expressing Xdsh-MA have their long axes distributed evenly between mediolateral and anteroposterior orientations. |
