Kyoto, Japan, March 6, 2002--- The Biomedical Group of Takara Shuzo Co., Ltd., which will be reorganized as TakaraBio Co., Ltd. on April 1, announced today that the Group has developed extremely efficient system for the recombinant protein production by using an Escherichia coli promoter of a cold shock protein in cooperation with Professor Masayori Inoue at the University of Medicine and Dentistry of New Jersey. This achievement will be presented at a symposium to be held at the National Institute of Health on March 7.

The system is an innovative one, in which an only protein of interest can be mainly over-produced in a very large amount, so usual purification steps of the protein can be avoided. The high productivity and specificity is achieved by using the Cold-shock vector and the system can be used as a protein over-producing machine.

Gene expression pattern of Escherichia coli cells with the Cold-shock vector is extremely changed depending on culture condition. Expression levels of genes expressed at the optimal temperature (37°C) are extremely reduced when the cells are exposed to the low temperature (10 to 15°C), cold-shock. On the other hand, a specific group of proteins called cold-shock proteins is produced in a large amount. The Cold-shock vector uses a promoter of the gene cspA, one of the cold-shock proteins. Scientists of the groups found a DNA sequence controlling expression of cspA protein. The sequence is used in the vector to increase expression levels of foreign genes at the low culture temperature. The maximal productivity of the foreign protein is 60 to 70% of total proteins in the E. coli cells and the system can be used as a protein-producing factory enabling efficient recovery and purification of the protein.

In a model experiment, the scientists made a Cold-shock vector containing interferon gamma gene downstream of the cspA promoter and the 5'-untranslated region of cspA mRNA. E. coli cells with the vector were cultured in the presence of 35S-methionine to radio-label newly synthesized proteins. Result showed that interferon gamma was not produced at all at 37°C, but was efficiently produced at 15°C and the amount reached more than 90% of newly synthesized proteins. Thus, the Cold-shock vector was shown to be useful for the highly efficient production of the foreign protein at low temperature.

The human genome has been almost sequenced, and now attention is shifting to studies of function of human genes. Proteomics is the most important technology to understand functions of genes in the post-genome era. For that purpose, structural analyses of proteins by NMR and X-ray are needed. The analyses require a large amount of protein of interest with high purity. The Cold-shock vector is a highly versatile tool to supply enough amounts of recombinant proteins for the analyses.

This indispensable technology for proteomics will be used in Takara's contract businesses and also non-exclusively licensed to pharmaceutical and biotechnology companies.

This article is translated from press release in Japanese for your convenience.