THERMOSENSITIVITY OF GREEN FLUORESCENT PROTEIN FLUORESCENCE UTILIZED TO REVEAL NOVEL NUCLEAR-LIKE COMPARTMENTS IN A MUTANT NUCLEOPORIN NSP1

Tagging proteins with the green fluorescent protein (GFP) from Aequore a victoria is a good means of analyzing protein localization in living cells. Nevertheless, GFP and a chimeric protein, GFP-nucleoplasmin, e xpressed in Saccharomyces cerevisiae were less fluorescent at high cul ture temperatures, Proteins synthesized at a low temperature retained their fluorescence despite a shift to a higher temperature. Hence, whe n a temperature-sensitive nsp1 mutant expressing GFP-nucleoplasmin was cultured at 23 degrees C and then shifted to 35 degrees C, we were ab le to exclusively monitor the localization of the protein synthesized prior to the temperature shift, This protein accumulated in novel nucl ear-like compartments devoid of DNA.