TRANSIENT EXPRESSION AND OIL BODY TARGETING OF AN ARABIDOPSIS OLEOSIN-GUS REPORTER FUSION PROTEIN IN A RANGE OF OILSEED EMBRYOS

An Arabidopsis oleosin gene including 860 bp of promoter as well as co ding sequence was fused to the reporter, beta-glucuronidase (GUS), In transient expression assays following particle bombardment, the Arabid opsis gene in both transcriptional and translational fusions with GUS was functional in a range of oilseed embryos as determined histochemic ally and fluorimetrically. Significantly, upon homogenization and sepa ration into cytoplasmic and oil body fractions, the complete oleosin-G US fusion was found to be targeted to the oil bodies in all of the het erologous species tested including canola, flax, soybean, sunflower, s afflower, cotton, castor bean, coriander as well as the monocot, corn. The utilization of oleosin protein fusions for recombinant protein ex pression should be applicable to this wide range of oilseed crops. Add itionally, the method of transient expression subcellular targeting sh ould be useful in determining structural motifs controlling intracellu lar trafficking of these proteins.