Fig. 8

YSL and gastrulation defects in Mybx1 mutants can be rescued by blocking Nodal signaling.

(A) DAPI-stained nuclei and E-cadherin immunostained membranes are clearly demarcated in lacZ and lefty1 RNA-injected control embryos. E-cadherin staining appears fragmented and number of YSL nuclei is increased in Mybx1 mutant embryos injected with control lacZ RNA (white arrowhead). In Mybx1 embryos injected with lefty1 RNA, the number of YSL nuclei is restored to normal levels and membrane staining does not appear fragmented. Bottom panels show higher magnification of area boxed in yellow; scale bar, 100 µm. (B) Histogram showing rescue of gastrulation and survival till prim5 stage by injection of lefty1 RNA but not lacZ RNA in Mybx1 mutants that were subjected to temperature shift at 23°C. Error bars show standard deviation from three experiments. Number of embryos is shown on top of the histogram. (C) Histogram showing gastrulation and % survival in embryos from ybx1^sa42/sa42;sqt^cz35/+ crosses and Mybx1 mutants subjected to temperature shift at 23°C. Most embryos from ybx1^sa42/sa42;sqt^cz35/+ crosses initiate and complete gastrulation in comparison to Mybx1 ^sa42 mutants. (D) Histogram showing survival at 23°C and genotypes of embryos from matings of ybx1^sa42/sa42;sqt^cz35/+, in comparison to Mybx1^sa42 embryos which do not survive at 23°C. The expected % for each genotype is 25% for Mybx1^sa42;sqt^cz35/cz35 and Mybx1^sa42;sqt^+/+, and 50% for Mybx1^sa42;sqt^cz35/+. All Mybx1^sa42;sqt^cz35/cz35 embryos (which have no Sqt signaling) survive, whereas many Mybx1^sa42;sqt^cz35/+ and Mybx1^sa42;sqt^+/+ do not survive at 23°C. Number of embryos scored is indicated above the histogram, and % observed for each genotype is indicated to the right of the colored bars.