Analysis of gene expression in ntla mutant embryos. A-J: Wild-type, ntla-/-, and ntlacs/cs embryos were placed at 17°C at shield stage, then incubated at 29°C the next morning (when the embryos were at bud stage) and raised to the 14-somite stage. Whereas ntla-/- embryos had essentially no expression of the presomitic genes tbx16 and tbx6l or the notochordal gene col9a2, ntlacs/cs, embryos had strong expression of all three genes. All these embryos were hybridized with the indicated probe at the same time and for the same length of time. K-P: In contrast, when ntlacs/cs embryos were kept continuously at 17°C, expression of all three genes was considerably diminished. Arrows show accumulation of col9a2 in the posterior of ntlacs/cs embryos.
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