US 5561236

The other dominant United States patent in the Bayer Crop Science portfolio originally assigned to Plant Genetic Systems NV and Biogen NV is US 5561236. This patent protects transgenic plant cells and plants containing a bar gene. Its bibliographic information is outlined below.

US 5561236
Title Genetically engineered plant cells and plants exhibiting resistance to glutamine synthetase inhibitors, DNA fragments and recombinants for use in the production of said cells and plants
Issue Date 1 Oct 1996 (expires 1 Oct 2013)
Assignees Plant Genetic Systems NV and Biogen NV (now Bayer Crop Science)
Inventors Leemans J, Botterman J, de Block M, Thompson C, Mouva R
Appl No and Filing Date US 07/525,300 17 May 1990
Priority US 07/131,140 (WO 87/05629 11-03-1987)
Abstract The invention relates to a DNA fragment containing a determined gene, the expression of which inhibits the antibiotic and herbicidal effects of Bialaphos and related products. It also relates to recombinant vectors, containing such DNA fragment, which enable this protective gene to be introduced and expressed into cells and plant cells.

This United States patent obtains priority from the same PCT application from which EP 242236 is derived. The claims in this patent are similar to the European patent in their objective; however they are not as broad.

Claim 1 claims a plant cell in which inactivation of a glutamine synthetase inhibitor is achieved by acetyl transferase activity of an introduced heterologous gene product. This contrasts to EP 242236, whereby the foreign gene to be inserted into the cell is only described in terms of its function. Claim 2 of US 5561236 further limits the introduced gene product referred to in Claim 1 as a polypeptide having an acetyl transferase activity with respect to phosphinothricin.

At this point we are not aware of other glutamine synthetase inhibitors that are inactivated by enzymatic acetylation. Hence, in practice, Claim 1 would likely refer to a bar gene product as specified in Claim 2. While Claim 1 is literally very broad, in reality the patentability requirements of enablement, written description and issues of interpretation would limit Claim 1 to that of Claim 2.

Dependent claims in the patent extend protection to whole plants, seeds of plants and any other plant tissue that contain the cells described in Claim 1.

Similarly to the European patent, the source of the gene product in the United States patent is not limited to a Streptomyces strain. Given this, the United States patent and the European patent likely protect the use of the bar gene, regardless of its source, in plants. Considering that both patents are part of the Bayer Crop Science portfolio, Bayer Crop Science have a controlling commercial position with respect to the use of the bar gene in both the U.S. and Europe.