The characterization of two functionally related genes, murH and lytG, in Escherichia coli

Simple item page
dc.contributor.authorBannister, Kelly Patriciaen_US
dc.date.accessioned2024-08-13T00:07:13Z
dc.date.available2024-08-13T00:07:13Z
dc.date.copyright1993en_US
dc.date.issued1993
dc.degree.departmentDepartment of Biochemistry and Microbiology
dc.degree.levelMaster of Science M.Sc.en
dc.description.abstractThe characterization of two distinct but apparently functionally related genes in E.coli, murH and lytG, is described. lytG represents a newly identified genetic locus, whereas the identification of murH was previously reported (85). The apparent relationship between these two genes is based on common suppression by the smhA locus and the similarities between murH and lytG mutant phenotypes. Both mutants exhibited temperature­sensitive growth and autolysis, characteristic of that mediated by peptidoglycan hydrolases, at the restrictive temperature. Attempts to subclone DNA fragments containing either murH or lytG complementing activity from phasmid-derived clones resulted in deletions within the fragments which indicated that, in both cases, some component of the complementing fragment was unstable when removed from the original phasmid clone. The murH deletion derivatives had lost the ability to restore growth at the restrictive temperature in murH mutants strains, suggesting that the deletion had encompassed at least a portion of the sequence from which the murH activity originated. The cloned fragment containing murH complementing activity was mapped to 16.0 minutes on the genetic map of the E.coli chromosome. This location was distinct from the 99.2 minute area to which the mutation in the murH mutant was previously mapped, indicating that a suppressor was likely responsible for the complementing activity found in the murH clone. DNA hybridization studies indicated that the cloned fragment harbouring murH activity contained DNA sequences similar to sequences within the 0-23 kb and 37.5-44.1 kb regions of the bacteriophage λ genome. The lytG complementing activity was subcloned into the multicopy number vector pUC19. Restriction mapping analysis indicated that the resulting lytG subclones contained deletions and possible rearrangements. Neither the IytG subclones, nor the original lytG phasmid-derived clone, could be detected on the E. coli K-12 chromosome by DNA hybridization, even though the mutation in the IytG mutant was previously mapped to the 25 minute position. This indicated that, similar to murH, a suppressor could be involved in restoring the ability of the IytG mutant to grow at the restrictive temperature. The cloned fragment containing IytG activity was shown, by hybridization studies and sequencing, to have significant identity to a DNA sequence within the 25.9-37.6 kb region of the phage λ genome. The possible basis for the instability, in the form of spontaneous deletions, of the cloned DNA fragments containing either murH or IytG activity, an explanation for the DNA sequence similarity with phage "A DNA, and the source of the presumptive suppression in the lytG and murH clones are discussed.en
dc.format.extent124 pages
dc.identifier.urihttps://hdl.handle.net/1828/17163
dc.rightsAvailable to the World Wide Weben_US
dc.titleThe characterization of two functionally related genes, murH and lytG, in Escherichia colien_US
dc.typeThesisen_US

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
BANNISTER_Kelly_Patricia_MSC_1993_558670.pdf
Size:
30 MB
Format:
Adobe Portable Document Format
Download

Collections

Electronic Theses and Dissertations (ETD)
 
University of Victoria Libraries

We acknowledge and respect the Lək̓ʷəŋən (Songhees and Esquimalt) Peoples on whose territory the university stands, and the Lək̓ʷəŋən and W̱SÁNEĆ Peoples whose historical relationships with the land continue to this day.