The characterization of lytF, a new member of the murH gene family of Escherichia coli

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dc.contributor.authorNoble, Michael-Anneen_US
dc.date.accessioned2024-08-15T16:35:13Z
dc.date.available2024-08-15T16:35:13Z
dc.date.copyright1993en_US
dc.date.issued1993
dc.degree.departmentDepartment of Biochemistry and Microbiologyen_US
dc.degree.levelMaster of Science M.Sc.en
dc.description.abstractThe characterization of a new gene, lytF, is described. The lytF mutation was mapped to 62.4 minutes on the Escherichia coli genetic linkage map, and was found to confer a temperature-sensitive colony forming and lysis phenotype. This mutant was of interest because its lytic phenotype resembled other previously described mutants that were defective in peptidoglycan metabolism. To further characterize the role of lytF, two extragenic suppressors of murH, a mutant whose lysis phenotype is similar to that of lytF and which appears to be defective in peptidoglycan metabolism, were transduced into the lytF strain. Both of these suppressors, designated smhA1 and smhB1, were found to suppress both the temperature­sensitive colony formation and lysis associated with the lytF mutation at high temperature. The smhA1- or smhB1-mediated suppression of the lytF temperature-sensitive colony formation was salt dependent, whereas the suppression of lysis was independent of the medium osmolarity. Because the ability of the smhA1 and smhB1 mutations to suppress lysis does not extend to mutational or antibiotic induced blockages in peptidoglycan biosynthesis, those mutations whose lytic phenotypes are suppressed by smhA1 or smhB1 have been proposed to be functionally related, and they have been designated as the murH family. Three observations indicate that the lytF gene may belong to the murH family. (i) The temperature-sensitive colony forming and lysis phenotype associated with lytF is similar to that expressed by other mutants in the murH family (murH, lytD, lytE). (ii) The lytF phenotypes are suppressed by the presence of smhAJ or smhBJ, which are specific to this family in terms of their suppression phenotypes. (iii) It is possible to select spontaneous smhA or smhB-like mutations in a lytF genetic background, indicating that the ability of smhA and smhB to suppress the lytF phenotype is more than just coincidence. It was also observed that the phenotype associated with the smhB locus may be variable depending on the allele. All smhB alleles characterized in this study share a common genetic linkage to the zbc-103 :: TnJO insertion, and are phenotypically dominant over the wild type smhB+ gene in complementation assays. However, the physical and suppression characteristics can differ substantially among alleles. It is currently unknown whether these differences in phenotype are due to different mutations in a single multifunctional gene, or different mutations in discrete, but closely linked genes.en
dc.format.extent76 pages
dc.identifier.urihttps://hdl.handle.net/1828/19141
dc.rightsAvailable to the World Wide Weben_US
dc.subjectUN SDG 15: Life on Landen
dc.titleThe characterization of lytF, a new member of the murH gene family of Escherichia colien_US
dc.typeThesisen_US

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