| Abstract: | A strain of Escherichia coli with a mutation in the promoter proximal gene ( uncI ) of the unc operon has been constructed by using a new gene replacement method. The mutation is a deletion of a defined sequence of 196 base pairs. It was constructed by homologous integration and segregation of a ColE1-derived recombinant plasmid containing the mutation, in a temperature-sensitive polA strain. The mutant strain is phenotypically unc+ but has a reduced growth yield compared to a normal sibling strain. |
