Fig. 3

Reduced Hh signaling in zic2a morphants prevents six3b expansion. (A-D) Zic2a depletion in smo^-/- mutant embryos. Zic2a-depleted WT siblings show expanded six3b in the telencephalon and diencephalon (green arrowheads in B, 120/151 embryos, n=2), whereas smo^-/- mutants injected with conMO lose six3b expression (C, 25/25 smo^-/- embryos, n=2). zic2aMO-injected smo^-/- mutants show upregulated, but anteriorly restricted, six3b expression (yellow arrowheads in D, 14/17 smo^-/- embryos, n=2). (E-H) Zic2a depletion in the presence of exogenous Hhip. Embryos injected with zic2aMO alone show expanded six3b (green arrowheads in F, 45/45 embryos, n=2), whereas embryos injected with hhip mRNA express six3b normally (black arrowheads in G, 43/43 embryos, n=2). Embryos co-injected with zic2aMO and hhip mRNA show rescued six3b expression (yellow arrowheads in H, 17/40 embryos, n=2). A-H are lateral views, anterior to the left. A′-H′ are ventral views of the same embryos, anterior to the left. Arrowheads point to the telencephalon and arrows to the diencephalon. Asterisks in A′-H′ illustrate six3b expression in the optic stalks. All embryos are shown at prim-5.