Submitted to: Molecular Genetics and Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2014
Publication Date: 9/29/2014
Publication URL: http://handle.nal.usda.gov/10113/60598
Citation: Johnson, E.T., Dowd, P.F. 2014. A non-autonomous insect piggyBac transposable element is mobile in tobacco. Molecular Genetics and Genomics. 289(5):895-902.
Interpretive Summary: One approach to discovering the functions of the thousands of genes present in crop plants is through the use of mobile DNA that disrupts normal gene function and causes measurable changes in plant structure, resistance or productivity. However, the mobile DNA currently used in these studies is not very efficient at producing single changes that can be traced to a single gene. A mobile piece of DNA, called piggyBac, has some unique properties that enables it to "jump" from one location in DNA to another and produce only a single change in the gene where it inserts. The element piggyBac is active in both insects and mammals. Our work demonstrates for the first time that piggyBac is also active in tobacco. This means that piggyBac can likely be used in gene studies for understanding the functions of tobacco genes, and probably can be used for other crops as well. This molecular tool could help discover the many unknown genes that contribute to crop health and yield, thereby increasing productivity, improving safety and lowering costs for consumers.
Technical Abstract: The piggyBac transposable element, originally isolated from a virus in an insect cell line, is a valuable molecular tool for transgenesis and mutagenesis of invertebrates. For heterologous transgenesis in a variety of mammals, transfer of the piggyBac transposable element from an ectopic plasmid only requires expression of piggyBac transposase. To determine if piggyBac could function in dicotyledonous plants, a two element system was developed in tobacco (Nicotiana tabacum). The first transgenic line constitutively expressed piggyBac transposase while the second transgenic line contained at least two non-autonomous piggyBac transposable elements. Progeny from crosses of the two transgenic lines were analyzed for piggyBac excision and transposition. Several progeny displayed excision events, and all the sequenced excision sites exhibited evidence of the precise excision mechanism characteristic of piggyBac transposase. Two unique transposition insertion events were identified that each included diagnostic duplication of the target site (TTAA). These data indicate that piggyBac transposase is active in a dicotyledonous plant, although at a low frequency.