Processing in Arabidopsis thaliana of a heterologous polyprotein resulting in differential targeting of the individual plant defensins

We previously developed a method for expression in Arabidopsis thaliana L. of transgenes encoding cleavable chimaeric polyprotein precursors containing two different plant defensins. The latter were linked by a naturally occurring linker peptide (LP4) originating from a polyprotein occurring in seeds of Impatiens balsamina. By using a hybrid linker peptide, consisting of the amino-terminal region of this LP4 linker peptide and the co-translationally cleaved foot-and-mouth-disease virus (FMDV) 2A sequence, we now show that it is possible to produce the individual plant defensins and to target them to different cellular compartments. This differential targeting indicates that the co-translational cleavage of the 2A sequence does not interfere with subsequent targeting of the protein downstream of the cleavage site, which has not been reported before in plants. We also demonstrate an enhanced protein production level in plants transformed with the polyprotein construct versus plants transformed with a single protein construct. (C) 2003 Elsevier Ireland Ltd. All rights reserved.