Validation of heat-inducible HSP70 and tick-specific 3xP3 promoters in ISE6 cells.

is an important vector of many pathogens, including the causative agent of Lyme disease. The gene function studies in and other ticks are hampered by the lack of genetic tools, including an inducible promoter for temporal control over transgene-encoding protein or double-stranded RNA. We characterized an intergenic sequence upstream of a heat shock protein 70 (HSP70) gene that can drive luciferase and mCherry expression in the cell line ISE6 (IsHSP70). In another construct, we replaced the minimal HSP70 promoter of the 3xP3 promoter with a minimal portion of IsHSP70 promoter and generated an -specific 3xP3 (Is3xP3) promoter. Both IsHSP70 and Is3xP3 have a heat-inducible expression of mCherry fluorescence in ISE6 cells with an approximately 10-fold increase in the percentage of fluorescent cells upon 2 h heat shock. These promoters described will be valuable tools for gene function studies.