METHODS OF GENE-TRANSFER AND THEIR POTENTIAL USE TO MODIFY MILK-COMPOSITION

Revolutionary new opportunities for the modification of animal performance have been created by the development of methods for gene transfer. Exploitation of these opportunities depends upon, 1). identification and cloning of coding sequences for proteins capable of having a desirable effect, 2). selection of a gene able to direct production of the protein to suitable tissues and stages of development, 3). identification of the regulatory sequences, 4). creation and transfer of the new fusion gene to a farm animal. The methods concerned, the practical problems and the potential benefits are discussed in relation to the project at Edinburgh to produce human therapeutic proteins in the milk of farm animals. Fragments of the ovine β-lactoglobulin gene fused to cDNA for the human therapeutic proteins clotting factor IX and α-1 antitrypsin have directed production of these proteins in the milk of transgenic mice and sheep. The factor IX was biologically active and co-migrated with authentic proteins, but present at low concentration. Recent observations suggest that fusion genes containing genomic clones direct production of higher concentrations of protein. © 1990.