Expression and activity of Cre recombinase in
lcp1(Cre-P2A-EGFP-CAAX) transgenic embryos.
A. Fixed transgenic embryo at 80% epiboly.
Immunohistochemical labeling shows robust nuclear signal in all EVL cells. red =
anti-Cre monoclonal anti-body, blue = DAPI nuclear stain.
B. Fixed wild type sibling embryo co-stained with the
specimen in (A). Although exposed to the same primary and secondary antibody
solutions, no nuclei stain red.
C. Fixed transgenic embryo, animal cap at 80% epiboly.
EGFP and Cre signals are positively correlated. Cells with bright membranes have
bright nuclei; cells with dim membranes have dim nuclei.
D. High magnification view of a single, Cre-positive EVL
nucleus (red) overlying multiple Cre-negative deep cell nuclei (blue).
E.
In vivo confirmation of Cre activity. After transient
transgenesis with a Cre reporter plasmid, a live cluster of transgenically
labeled periderm cells (green) expresses recombinant RFP-tagged mouse CD8a
(red). For details, see Methods.