Isolation and behavior of Escherichia coli deletion mutants lacking chemotaxis functions - PubMed (original) (raw)

Isolation and behavior of Escherichia coli deletion mutants lacking chemotaxis functions

J S Parkinson et al. J Bacteriol. 1982 Jul.

Abstract

Six Escherichia coli che loci (cheA,-B,-R,-W,-Y, and Z) are located in two adjacent operons that map at minute 42 on the chromosome. Point mutants defective in any of these six functions have aberrant swimming patterns and are generally nonchemotactic. Deletions within the two major che gene operons were isolated in order to examine epistatic interactions among these genes. We first constructed a specialized transducing phage (lambda che22), which carries both of the che operons and their associated promoters. Deleted lambda che22 derivatives were selected by chelating agent inactivation, and these derivatives were characterized by mapping them against a series of host strains with point mutations. Representative nonpolar deletions were then transferred into the E. coli chromosome by homologous recombination. Although the phenotype of cheR mutants (smooth swimming) was expected to be epistatic to that of cheB mutants (tumbly swimming), we found that deletion mutants lacking both of these functions exhibited frequent directional changes or tumbling episodes as they swam. An examination of larger deletions indicated that both the cheA-cheW and cheY-cheZ functions were required for the anomalous tumbling behavior observed in these mutants. Loss of the cheB function was also correlated with an inverted behavioral response to sodium acetate, a strong repellent of wild-type cells. These findings indicate that an important component of the signal transducing machinery may be altered in cheB mutants.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Genetics. 1967 Jul;56(3):363-73 - PubMed
    1. Genetics. 1969 Jan;61(1):61-6 - PubMed
    1. J Mol Biol. 1971 Mar 14;56(2):369-84 - PubMed
    1. Proc Natl Acad Sci U S A. 1972 Sep;69(9):2509-12 - PubMed
    1. Nature. 1972 Oct 27;239(5374):500-4 - PubMed

Publication types

MeSH terms

LinkOut - more resources