TAC-TICS: Transposon-based insect control systems

We describe a system in which a specific population of a single pest insect type is targeted for management by making that population susceptible to control. In this paper we discuss the four key components of this genetic control system: transformation of the targeted insect; dissemination of the engineered construct throughout the targeted population; the inducible promoter to activate the expression of the fourth component; the incapacitating gene or genes. We describe the progress made in transformation of insects other than Drosophila. Using populations of model organisms, we show that transposon constructs can spread quite rapidly through a targeted population. We provide evidence that the multiplicative transposition process, which drives the spread of the engineered transposon construct, is not highly en-or prone and thus the use of TAC constructs in insect populations is feasible. The genes that might be used as relatively insect-specific incapacitating genes if over-expressed, mis-expressed or inactivated in specific insects or insect tissues include: genes that encode a variety of hormones and neuropeptides and their receptors; developmental selector genes, that is,. genes that control entry or exclusion of certain developmental pathways; genes that control components of signal cascades, which coordinate most of the physiological responses within and between tissues in an organism; cell cycle control genes; paralytic peptides; and many others. Finally we discuss a novel cell-based functional assay system which should allow investigators to test the function of inducible promoters, and some potential incapacitating genes, in a wide variety of insect systems prior to creating transgenic insect. Use of this in vivo test system should result in a significant saving of time in creating and testing specific TAC constructs.