BREEDING SYSTEM CONTAINING BREEDING MARKERS NOT CONNECTED WITH ANTIBIOTIC RESISTANCE

摘要

A selection system lacking antibiotic resistance genes, which is based on the use of the araD gene as a selection marker that carries a vector embedded in a bacterial strain deficient in the araD gene. The araD gene from E. coli encodes L-ribulose-5-phosphate-4-epimerase. The method of selection of cells transformed with a plasmid that contains the araD gene. A non-antibiotic selection marker makes this system suitable for the production of therapeutic agents. The araD gene is not essential for host growth, but manipulation with it affects growth in some selective conditions. AraD deletion leads to accumulation of a substance that is toxic to the host, but not to humans. The araD gene is relatively small, and therefore a small plasmid can be constructed that requires less energy to replicate and leads to an increased growth rate and yield.