Title: Transposable elements for insect transformation Authors
|O'Brochta, David -|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: July 27, 2011
Publication Date: February 1, 2012
Citation: Handler, A.M., O'Brochta, D.A. 2012. Transposable elements for insect transformation. In: Gilbert, L.I.,editor. Insect Biochemistry and Molecular Biology. London, United Kingdom: Academic Press. p. 90-133. Interpretive Summary: The creation of genetically transformed, or transgenic, strains of economically important insects for the development of more effective biological control programs is a major goal of our laboratory at the Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, FL. Development of this methodology and strategies to effectively and safely utilize transgenic insects for biological control will depend upon a comprehensive knowledge of the mechanisms involved in transposon movement, the types of biocontrol strategies that transgenic strains can improve, and a critical analysis of potential risks involved in the release of transgenic insects. This article addresses the current knowledge of the transposable element vectors used to mediate germ-line transformation of insect psecies. The potential use of genetically trasnformed strains to improve the sterile insect technique and in new strategies using conditional lethal transgenes for autocidal biological control is discussed. Finally, factors that affect stability of transposon vectors and methods to improve their stability after genomic integration are addrssed in the context of the field release of these strains. New transformation vectors are described that allow targeting of transgenes into predefined acceptor sites in the genome, with stabilization facilitated by removal of vector sequences needed for mobility. This information will be used to facilitate the creation of effective and ecologically safe transgenic insects, as well as methods to test and assess these attributes.
Technical Abstract: The germ-line of more than 35 species from five orders of insects have been genetically transformed, using vectors derived from Class II transposable elements. Initially the P and hobo vector systems developed for D. melanogaster were not applicable to other species, but four transposons found in other species, Hermes, Minos, Mos1, and piggyBac, were found to be widely functional in most insects. Genetic marker discovery and development have been equally important to vector development. Originally, cloned eye color genes from Drosophila that complemented existing mutations in other insects were used, but now more widely applicable dominant-acting fluorescent protein genes are effective transformation markers and reporters for gene expression. Transformation technology is advancing at a fortuitous time when genomics is providing resources necessary for transgenic strain development in pest species to control their population size and behavior. Transposon-based transformation methods are also advancing insertional mutagenesis techniques, such as enhancer traps and transposon tagging, to facilitate the gene discovery and functional analysis that provides these resources. Together, efficient and routine methods for transposon-mediated germ-line transformation and genomics analysis should provide tools critical to the advancement of our understanding and control of insect species.