GFP - GREEN FLUORESCENT PROTEIN-A VERSATILE GENE MARKER FOR ENTOMOPATHOGENIC NEMATODES

Gene expression and protein distribution within cells may be monitored using reporters, such as, beta-galactosidase, firefly luciferase, and bacterial luciferase. These reporter systems require exogenously adde d substrates and cofactors which kill the cells or organism. The jelly fish (Aequorea victoria) green fluorescent protein (gfp) gene has been used as a marker for gene expression in Caenorhabditis elegans. Becau se exogenous substrates or cofactors are not required for the fluoresc ence, gfp can be used to monitor gene expression in living organisms. Natural autofluorescence in nematodes however, can, hinder the use of such markers. We studied autofluorescence in entomopathogenic nematode s to explore the use of gfp as a marker for gene expression. All stage s of Heterorhabditis and Steinernema spp. autofluorescent ranged from green to light yellow, the intensity of autofluorescence increased wit h the age of nematodes. We used gfp that was under the control of mec- 4 promoter from C. elegans and injected the plasmid (pGFP/mec-4) into the gonad of Heterorhabditis bacteriophora using microinjection. Gfp w as expressed in H. bacteriophora and was easily identified in the tail region of the nematode. Expression of mec-4 indicates the presence of touch receptors neurons in H. bacteriophora at the same position as i n C. elegans. We conclude that gfp is an efficient marker for gene exp ression in entomopathogenic nematodes.