Fig. 3.

Maturin knockdown results in neural plate expansion. (A–F″) Design and test of Maturin morpholino activity. (A) Sequence alignment of a and b homeologs of X. laevis maturin showing relative position of the Maturin morpholino MatMO2 (red overline). (B) Schematic of the Mat target-YFP reporter construct used to test morpholino activity. (C) Western blots were used to detect the expression of YFP and β-actin (loading control) in extracts prepared from embryos injected with the indicated morpholino, and cRNA coding for YFP or Mat target-YFP. (D–F″) Brightfield (D, E and F), mCherry fluorescent (D′, E′ and F′) and YFP fluorescent (D″, E″ and F″) images of stage 15 embryos unilaterally injected with cRNA for mCherry and Mat target-YFP alone (D – D″), with CoMO (E–E″), or MatMO2 (F–F″). (G–M) Neural plate expansion following Maturin knockdown. The extent of neural plate expansion was determined by comparing the distance between the embryonic midline (white dashed line) and outer edge of the neural ridge on the control (uninjected) and injected side of embryos injected with CoMO (G–I) or MatMO2 (J–L). In situ hybridization for sox2 (H, K) and rax (I, L) was used to more precisely quantitate the extent of neural plate expansion (M). Graph shows the size of the sox2 and rax expression domains in the uninjected and injected side of either CoMO or MatMO2 embryos. Error bars show the s.e.m. Asterisks indicate P-values calculated using a one-way ANOVA analysis (ns P>0.05; *** P<0.0001). Right side (viewer’s perspective) of all embryos is the injected side. Scale bars, 400μm.