Figure 1. Blastomere injection and activation of gene expression

A: The major blastomere progenitor of the retina (D1.1.1) in a 32-cell stage embryo was injected with mRNAs encoding hormone-inducible rx1or pax6 constructs and gfp as a lineage tracer. B: Exogenous gene expression was induced in early (Stage 12) or late (Stage 16) eye fields by incubation in dexamethasone solution. Hormone treatment was continued throughout the culture period. (C) Embryos were raised to tadpole stages (stage 44/45) when amacrine cell subtypes have differentiated and can be labeled with neurotransmitter-specific antibodies.