University of Illinois Urbana-Champaign

Biochemical and molecular characterization of chemotaxis genes in Bacillus subtilis

Ying, Ching-Wen

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Description

Title
Biochemical and molecular characterization of chemotaxis genes in Bacillus subtilis
Author(s)
Ying, Ching-Wen
Issue Date
1990
Doctoral Committee Chair(s)
Ordal, George W.
Department of Study
Biochemistry
Discipline
Biochemistry
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Chemistry, Biochemistry
Language
eng
Abstract
  • The cheF gene, an essential gene for chemotaxis in B. subtilis was cloned, localized and characterized. This gene is contained in a 7.7 kb EcoR1 DNA fragment that was isolated from a $\lambda$ Charon 4A B. subtilis chromosomal DNA library. A 0.7 kb Pst 1 DNA fragment of this 7.7 kb EcoR1 fragment was subcloned into an expression vector, pSI-1 and shown to complement the cheF mutation both for chemotaxis and for methanol formation in response to the addition of attractants.
  • The cheF mutant is defective in the positive stimuli pathway (addition of attractants and removal of repellents) but normal in the negative stimuli pathway (removal of attractants and addition of attractants). Unlike wild type B. subtilis, the cheF mutant failed to transfer methyl groups from methyl-accepting chemotactic proteins to a carrier, molecule X on addition of attractants. The deduced function of CheF in chemotaxis appears to be interacting with methylesterase, the enzyme responsible for removal of methyl groups from methyl-accepting chemotactic proteins.
  • The transcription unit which the cheF is located within was characterized. This transcription unit maps near pyrD and spcB, and at least ten complementation groups were found to be cotranscribed in this transcription unit. The regulation of this transcription unit seems to be under the control of SigA, the primary $\sigma$ factor in B. subtilis at the transcriptional level. Inspection of the promoter DNA sequence of this transcription unit revealed a potential consensus sequence for SigA promoters. Tn917-derived chemotaxis mutants whose mutations map near hisA and metC were analyzed. The expression of genes from these two loci requires the presence of an alternate $\sigma$ factor, SigD.
Type of Resource
text
Permalink
http://hdl.handle.net/2142/22824
Copyright and License Information
Copyright 1990 Ying, Ching-Wen

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