The present invention describes novel polypeptide structures based on oleosin molecules which are capable of being targeted to oil bodies in plants. The modified oleosin polypeptides are obtained by performing modifications in the hydrophobic domain encoding sequence of an oleosin cDNA. The present invention describes methods to obtain such polypeptides in vivo. The novel oleosins may be used to deliver a recombinant (non-oleosin) protein to oil bodies.