Fig. 7

Increased presence of Pax2a in hand2-expressing cells of hand2 mutants.

(A–B) In situ hybridization depicts presence of hand2 expression in hand2 morphants (B); dorsal views, anterior to the left, at the 10 somite stage. There is no evident loss of hand2-expressing cells in hand2 morphants; moreover, hand2 expression levels appear higher in the context of hand2 loss-of-function. Scale bar represents 100 μm. (C–D) Immunofluorescence for Pax2a and GFP in wild-type (C) and han^s6 mutant (D) embryos, both carrying Tg(hand2:EGFP); dorsal views, anterior to the left, of three-dimensional reconstructions at the 12 somite stage, as in Figure 4G. (C'–D''') Magnification of 250 µm long regions from (C) and (D) used for quantification of the numbers of GFP⁺ and Pax2a⁺ cells in wild-type and han^s6 mutant embryos. Yellow dots indicate GFP⁺ cells, white dots indicate Pax2a⁺ nuclei, and examples of GFP⁺ Pax2a⁺ cells are indicated by white arrows. Intensity of Pax2a⁺ staining varied from strong (for example, green arrows) to weak (for example, yellow arrows). Scale bars represent 100 μm (C, D) and 25 μm (C'–D'''). (E) Bar graph indicates the average numbers of GFP⁺ cells and GFP⁺ Pax2a⁺ cells per 100 µm of IM in wild-type and han^s6 mutant embryos; error bars indicate standard deviation. Asterisk indicates a statistically significant difference compared to wild-type (p<0.0001, Student’s t test; n = 13 for wild-type and n = 10 for han^s6).