Expression of sox17 and foxj1a. (A-E) Expression of sox17 in DFCs at 90% epiboly. In control embryos, 89.5% of embryos showed normal expression (A, n=88). In aplnra morphants, three kinds of expression pattern were discovered: mild decreased (B, 52.4%, n=89, p<0.001), scattered (C, 21.3%, n=89, p<0.001) and decreased (D, 19.6%, n=89, p<0.01). The area of sox17 expression was measured and in control embryos, the average level was 3.68x103 uM2 (E. e1 group, n=19), the average area in aplnra morphants was 2.55x103 uM2 (E. e2 group, n=22, p<0.05). Sox17 expression areas were also measured for aplnrb morphants, aplnra+b morphants, apela morphants, embryos injected with apln mRNA and embryos injected with apln mRNA, respectively (E, e3-e7 group). The average areas were 3.63x103 uM2 (E, e3 group, aplnrb morphants, n=15, p>0.05), 2.53x103 uM2 (E. e7 group, aplnra+bmorphants, n=15), 3.28x103 uM2 (E, e4 group, apela morphants, n=15, p<0.05), 2.46x103 uM2 (E, e5 group, apln mRNA, n=15, p<0.01) and 2.64x103 uM2 (E, e6 group, apela mRNA, n=15, p<0.001), these data indicated sox17expression was down reglated in all these treated embryos, excepted for aplnrb morphants. (F-J) Analysis of foxj1aexpression. Foxj1a was expressed in DFCs at 90% epiboly in control (F) and treated embryos (G, H). Compared with control embryos (F, 80.5%, n=82), foxj1a was greatly down regulated in aplnra morphants (H-I, 68.9%, n=87, p<0.001) as well in aplnra+b morphants (I, 65.7%, n=76, p<0.001), but not in aplnrb morphants (I, 18.9%, n=74, p>0.05). Foxj1a expression area in control embryos, aplnra morphants, aplnrb morphants and aplnra+b morphants were average 3.75 x103 uM2. 2.56 x103 uM2, 3.57 x103 uM2 and 2.39 x103 uM2 respectively (I). Compared with that in control embryos, q-PCR experiment showed the quantity of foxj1a expression in aplnra morphants and aplnra+bmorphants were down-regulated with 0.48 folds and 0.46 folds respectively, while the expression of foxj1a in aplnrbmorphants was not affected (J). *, p<0.05; **, p<0.01; ***, p<0.001; NS, not significant.