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Fig. 3. An antisense morpholino oligonucleotide targeted against X. tropicalis Elk-1 has less effect on gene expression than does XElk-1-EnR but does interfere with muscle and notochord differentiation. (A, C) Embryos injected with a control morpholino oligonucleotide showing expression of Xbra (A) and XtEgr-1 (C). (B, D) Embryos injected with an antisense morpholino oligonucleotide directed against XtElk-1. Note delay in blastopore closure caused by the MO (compare A and B). Expression of Xbra is only slightly affected by XtElk-1 MO (B) but expression of XtEgr-1 is more significantly reduced. (E, F) Expression levels of XtMyoD are substantially decreased by XtElk-1 MO. (E) An embryo injected with a control MO; (F) an embryo injected with an antisense morpholino oligonucleotide directed against XtElk-1. (G, J) Control embryos at tailbud stages stained with 12/101 (G) or MZ15 (J). (H, K) Embryos injected with an antisense morpholino oligonucleotide targeted against XtElk-1. Note the reduction in muscle (H) and notochord (K) differentiation. (I, L) Rescue of the effects of the MO targeted against XtElk-1. Muscle (I) and notochord (L) formation are both restored in embryos injected with XElk-1 mRNA as well as XtElk-1 MO. Results in G-L were obtained in three independent experiments. Eighty-five embryos were injected with our control MO, of which 90% appeared normal; 109 were injected with XtElk-1 MO, of which 13% appeared normal; and 118 were injected with XtElk-1 MO together with XElk-1-myc mRNA, of which 79% appeared normal. |
