Loss of an Essential Function of Escherichia coli by Deletions in the thyA Region

AUTOR(ES)
RESUMO

In an attempt to obtain deletions in the thyA gene, an abnormal lysogen of λ having the prophage inserted between the thyA and lysA genes was induced, and the surviving cured cells were examined for Thy− and Lys− mutants. In nearly 10,000 cured cells, 184 Lys− but no Thy− mutants were found. At the same time, the induced λ phage contained an approximately equivalent number of λthyA+ and λlysA+ transducing particles. By contrast, in a strain with the genotype F′ thyA−lysA+/ thyA+lysA+, induction of the abnormal λ lysogen gave rise to many Thy− mutants in the cells cured of the prophage. In these Thy− mutants it was not possible to eliminate the episome with acridine orange, although the episome could be removed in control cultures with a thyA+ allele in the resident gene. Therefore, it was suggested that deletion of a gene in the region of the chromosome from the position of the insertion of the λ prophage through the thyA gene caused loss of an essential and diffusible function.

Documentos Relacionados