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Figure 4. er71 is required for vascular development. A: Microinjection of X. laevis-specific er71 antisense morpholino (er71-MO-xl) leads to a reduction in vascular development. At NF stage 37, knock-down of er71 function leads to a severe reduction in the expression of vascular marker genes flk1, Ami, and ve-cadherin in the vitelline veins, in the intersomitic veins, in the posterior cardinal vein, and in the vascular structures of the head. To trace the fate of the microinjected morpholinos, synthetic mRNA for β-galactosidase was co-injected. In control morpholino-injected embryos, expression of marker genes appears normal. B: er71-MO-xl specifically reduces translation of er71-mRNA in a coupled transcription/translation assay. ER71 protein expressed from a pCS2+ vector that contains 5′-UTR and the N-terminus of er71 is reduced upon addition of er71-MO-xl but not by the application of a X. tropicalis-specific antisense morpholino (er71-MO-xt). C: Sequences of X. laevis- and X. tropicalis-specific antisense morpholinos, aligned to the initial AUG of er71-mRNA. isv, intersomitic veins; pcv, posterior cardinal vein; vv, vitelline veins. |
