However, worm researchers have had a limited toolkit for controlling gene activation. elegans has been an important model system for studying the roles of genes in animal development and physiology. Genes turn on and off as a natural part of development. We show that we can use this to inactivate synaptic transmission in all neurons or a subset of neurons in a FLP-dependent manner. As a test of the system, we have driven the light chain of tetanus toxin, a protease that cleaves the synaptic vesicle protein synaptobrevin. Finally, FLP expression can be driven by a tissue specific promoter to provide expression in a subset of cells that can only be addressed as the intersection of two available promoters. In addition, the temporal switch is permanent, rather than acute, as is usually the case for heat-shock driven transgenes. We demonstrate that heat-shock-driven FLP recombinase adds temporal control on top of tissue specific expression provided by the transgene promoter. The constructs are designed using the multisite Gateway system, so that promoters and coding regions can be quickly mixed and matched. We have introduced two fluorescent reporters into the system: a red reporter for promoter activity prior to FLP expression and a green reporter for expression of the gene of interest after FLP expression. This sequence can be excised by FLP recombinase to bring together the promoter and the coding region. The “off cassette” is composed of a transcriptional terminator flanked by FLP recognition targets (FRT). Transcription is blocked by the presence of an “off cassette” between the promoter and the coding region of the desired product. Here we use FLP to temporally and spatially control gene expression in the nematode C. The FLP enzyme catalyzes recombination between specific target sequences in DNA.

DNA.com by Morton Chalfy