MZpitx2c mutants are correctly patterned but exhibit defects in spatial organization.
(a–g) Analysis of goosecoid (gsc) (a), noto/flh (b, c), eve1 (d), wnt8a (e), tbx16 (f), and sox17 (g) expression by in situ hybridization. Expression of gsc (dorsal organizer) at 80% epiboly is indistinguishable between MZpitx2c mutants and wild types (a). At 60% epiboly, MZpitx2c mutants display an expanded domain of noto expression (axial mesoderm) (b) and subsequently a shorter and wider notochord at the one somite stage (ss) (c). A higher magnification of the boxed regions in panel c is shown in the lower panels. The eve1 expression domain (ventral mesoderm) is expanded dorsally in MZpitx2c mutants (d) (outlined by dashed lines and indicated by arrows in the vegetal pole views), and no obvious changes were observed in wnt8a expression (embryonic margin) (e). Expression of tbx16 (paraxial mesoderm) is disrupted in the dorsal region of MZpitx2c mutants (f). Expression of sox17 (endoderm) reveals defects in dorsal forerunner cell migration (arrowheads) in 80% epiboly MZpitx2c mutants (g). a-c and e-g: dorsal views, animal pole to the top; a-b: animal pole views, dorsal to the right of the image; d: lateral views, dorsal to the right of the image; d-e: vegetal pole views, dorsal to the right of the image. ‘n’ refers to the number of embryos with the expression pattern shown over the total number of embryos analyzed. AP, animal pole; D, dorsal; V, ventral. Scale bars, 100 μm.