Insertion sequence-free bacteria
The present invention provides a bacterium having a genome that is genetically engineered to be smaller than the genome of its native parent strain. A bacterium with a smaller genome can produce a commercial product more efficiently. The present invention also provides methods for deleting genes and other DNA sequences from a bacterial genome. The methods provide precise deletions and seldom introduces mutations to the genomic DNA sequences around the deletion sites. Thus, the methods can be used to generate a series of deletions in a bacterium without increasing the possibility of undesired homologous recombination within the genome. In addition, some of the methods provided by the present invention can also be used for replacing a region of a bacterial genome with a desired DNA sequence.
1. An isolated Escherichia coli bacterium lacking all IS1, IS2, IS3, IS5, IS150 and IS186 insertion sequences, wherein the genome of said bacterium is between 4.41 and 3.71 Mb.
2. The bacterium of claim 1 , wherein the genome of the bacterium is between 4.31 Mb and 3.71 Mb.
3. The bacterium of claim 1 , wherein the genome of the bacterium is between 4.27 Mb and 3.71 Mb.
4. The bacterium of claim 1 , wherein the genome of the bacterium is lacking the nucleic acid sequence of a deletion set forth in Table I or Table II.
5. The bacterium of claim 1 , wherein the chromosome of the bacterium does not comprise scars.