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Figure 4. Knockdown of xHtrA1 Promotes Anterior Development and Impairs Mesoderm and Neuronal DifferentiationMorpholino oligonucleotides (MOs) were injected at the 2-cell stage (8 pmol per embryo); xHtrA1 or nontargeted xHtrA1* mRNA (see Experimental Procedures) were injected into each blastomere at the 4-cell stage (160 pg total).(A) xHtrA1-MO targets both Xenopus laevis HtrA1 pseudoalleles.(B) xHtrA1-MO, but not control-MO, inhibits translation of injected xHtrA1 mRNA at stage 9. xHtrA1-MO does not affect the protein synthesis of xHtrA1* mRNA.(C) xHtrA1-MO blocks endogenous xHtrA1 protein expression at stage 12.(D–G) xHtrA1-MO leads to enlarged head, decreased eye and shortened tail formation after injection into the animal pole and margin of each blastomere.(H and I) A single marginal injection of xHtrA1-MO blocks Xbra expression.(J–M) Animally injected xHtrA1-MO broadens the expression domains of BF1 and En2, and restricts Rx2a expression.(N and O) A single animal injection of xHtrA1-MO reduces N-tubulin expression.(P–S) Marginally injected xHtrA1-MO depletes the posterior Sizzled expression domain (arrowhead). xHtrA1* mRNA reverts the effect of xHtrA1-MO.Indicated phenotypes were observed in D, 92/92; E, 60/60; F, 18/18; G, 51/51; H, 17/19; I, 22/28; J, 20/20; K, 35/57; L, 10/10; M, 42/43; N, 15/19; O, 16/18; Q, 41/74; R, 19/19; and S, 15/15 embryos. |
