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Fig. 2. Visualization of PAI-1-GFP in cellular migration tracks. Schematic of a
pEGFP-1-based vector in which a chimeric transcript consisting of 1.3 kb of
PAI-1 coding sequences and GFP is expressed under the control of a 0.8 kb
PAI-1 `promoter' (A). Transfection of RK cells and reseeding in
serum-containing medium resulted in synthesis of PAI-1-GFP detected initially
in perinuclear Golgi-like structures (B). Approximately 6-12 hours later,
PAI-1-GFP can be found in the matrix (probably vitronectin)-rich undersurface
region upon removal of cells with saponin (C). The green `footprint' of a
single cell is shown in C. Seeding of PAI-1 promoter-PAI-1 coding-GFP
transfectants at low density in EGF-containing medium provides for the clear
visualization of the chimeric PAI-1-GFP protein in cellular migration trails
(D). The small bright image at the extreme right of the trail is the cell
body. Transfection of RK cells with the PAI-1 promoter-PAI-1 coding-GFP vector
followed by growth to confluency and subsequent scrape injury indicated that
the resulting motile population deposited GFP-'tagged' PAI-1 into the cellular
migration trails similar to that illustrated in D.