Overexpressing tagged proteins in plants using a modified gateway cloning strategy.

In recent years, sequence-specific recombination cloning methods such as the Gateway system have become increasingly popular for (over)expressing tagged proteins in high-throughput investigations in many different organisms, including plants. Because of their versatility and ease of use, these methods have gained favor in low- and medium-throughput investigations as well. However, due to the recombination step, the resulting fusion proteins contain long and often highly charged polylinker sequences that can interfere with their physiological function. Furthermore, in some cases the gene of interest must be cloned twice (once with and once without a stop codon) for N- and C-terminal tagging. Here, we present a hybrid combinatorial cloning strategy that overcomes many of these limitations. In the first step, the gene of interest is cloned into an entry vector containing standardized cloning sites with the desired N- or C-terminal tag and an optimized polylinker sequence. A Gateway recombination reaction is used to transfer the protein-tag fusion from the entry clone to a Gateway destination vector with the desired promoter and selectable marker for the organism of interest. As experimental requirements evolve, constructs for expressing the protein of interest with the desired tag, promoter, and selectable marker or other features can rapidly and easily be created.