NEW UNSTABLE VARIANTS OF GREEN FLUORESCENT PROTEIN FOR STUDIES OF TRANSIENT GENE-EXPRESSION IN BACTERIA

Use of the green fluorescent protein (Gfp) from the jellyfish Aequorea victoria ia is a powerful method for nondestructive in situ monitorin g, since expression of green fluorescence does not require any substra te addition. To expand the use of Gfp as a reporter protein, new varia nts have been constructed by the addition of short peptide sequences t o the C-terminal end of intact Gfp. This rendered the Gfp susceptible to the action of indigenous housekeeping proteases, resulting in prote in variants with half-lives ranging from 40 min to a few hours when sy nthesized in Escherichia coli and Pseudomonas putida. The new Gfp vari ants should be useful for in situ studies of temporal gene expression.