Patent ID: 6610529
Filing Date: 2003-08-26
Classification: C12N

Abstract:
An isolated microbial cell comprising a genetically engineered Environmentally Limited Viability System, wherein the cell is viable in a permissive environment and non-viable or temporarily viable in a non-permissive environment, the system comprising(a) an essential gene located on an extrachromosomal vector, wherein expression of the essential gene in the cell is essential to the viability of the cell, the essential gene is expressed when the cell is in the permissive environment and is not expressed or temporarily expressed when the cell is in the non-permissive environment, and wherein the essential gene is a copy of a wild-type gene of the microbial cell; and (b) a lethal gene located on an extrachromosomal vector, wherein the expression of the lethal gene is regulated by an expression product of a regulatory gene located on the chromosome of the cell, and wherein expression of the lethal gene is lethal to the cell and the lethal gene is expressed when the cell is in the non-permissive environment but not when the cell is in the permissive environment, wherein the wild-type essential gene is inactivated in the cell, and wherein the essential gene is essential for metabolism, growth, cell wall integrity, or cell membrane integrity of the cell.