Controllable alteration of cell genotype in bacterial cultures using an excision vector.
We have used recombinant DNA techniques to construct a derivative of phage lambda, called an excision vector, which retains only those functions necessary for conditional maintenance of lysogeny and integration/excision. The tyrA+ gene was cloned on this excision vector, integrated into the Escherichia coli chromosome, and stably maintained and expressed under permissive conditions. Upon shift to non-permissive conditions, the excision vector and its passenger gene were very efficiently excised from the chromosome and lost, leaving a culture of Tyr- bacteria. This illustrates a new class of conditional mutations in which the genotype changes in response to external stimuli.
Balakrishnan
R
R
BioTechnica International, Inc., Cambridge, MA 02140.
Backman
K
K
D010582:Bacteriophage lambda / Q000235:genetics*; D002876:Chromosomes, Bacterial / Q000502:physiology; D003001:Cloning, Molecular / Q000379:methods; D004262:DNA Restriction Enzymes; D004274:DNA, Recombinant / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D005822:Genetic Vectors; D005838:Genotype
D004274:DNA, Recombinant; D004262:DNA Restriction Enzymes