GREEN FLUORESCENT PROTEIN AND ITS DERIVATIVES AS VERSATILE MARKERS FOR GENE-EXPRESSION IN LIVING DROSOPHILA-MELANOGASTER, PLANT AND MAMMALIAN-CELLS

We have investigated the utility of the green fluorescent protein (GFP ) as a marker for gene expression in living adult Drosophila melanogas ter (Dm) and cultured plant and mammalian cells, Using Dm, we generate d transgenic flies bearing a glass-responsive gfp fusion gene to test the utility of GFP as a spatial reporter. In the adult living fly, GFP is clearly visible in the ocelli and the eye. We have optimized the u se of filters for distinguishing the GFP signal from abundant autofluo rescence in living Dm. In addition, we have used GFP to identify photo receptor cells in pupal eye cultures that have been fixed and stained according to standard histological procedures. GFP was also detected i n individual living plant cells following transient transfection of so ybean suspension cultures, demonstrating that GFP is an effective tran sformation marker in plant cells, Similarly, transient transfection of mammalian cells with a modified form of GFP, S65T, allowed detection of single living cells expressing the reporter, This modified form of GFP gave a robust signal that was resistant to photobleaching. We then used a CellScan system exhaustive photon reassignment (EPR) deconvolu tion algorithm to generate high-resolution three-dimensional images of GFP fluorescence in the living cell.