FUNCTIONAL GENOMICS - PROBING PLANT GENE-FUNCTION AND EXPRESSION WITHTRANSPOSONS

Transposable elements provide a convenient and flexible means to disru pt plant genes, so allowing their function to be assessed. By engineer ing transposons to carry reporter genes and regulatory signals, the ex pression of target genes can be monitored and to some extent manipulat ed. Two strategies for using transposons to assess gene function are o utlined here: First, the PCR can be used to identify plants that carry insertions into specific genes from among pools of heavily mutagenize d individuals (site-selected transposon mutagenesis). This method requ ires that high copy transposons be used and that a relatively large nu mber of reactions be performed to identify insertions into genes of in terest. Second, a large library of plants, each carrying a unique inse rtion, can be generated. Each insertion site then can be amplified and sequenced systematically. These two methods have been demonstrated in maize, Arabidopsis, and other plant species, and the relative merits of each are discussed in the context of plant genome research.