Green fluorescent protein microscopy (A) and cytochemistry (B) confirms that EgadMe enables in vivo imaging of mRNA expression in the transparent embryo of an African clawed frog (Xenopus laevis). It was injected at the two-cell stage of its development. Both cells received EgadMe, while only one cell was also injected with mRNA for b-galactosidase. The asymmetric pattern of fluorescence that emerged as the tadpole developed (C) indicates that activated EgadMe was trapped inside the cells that descended from the cell injected with mRNA for b-galactosidase.
(Provided by T. Meade)