Mountain View
biomedical and healthCAre Data Discovery Index Ecosystem
help Advanced Search
Title: Mutation of the RNA polymerase β-subunit gene promotes hetero-to-homo conversion of ß-lactam resistance of methicillin-resistant Staphylococcus aureus      
dateReleased:
08-27-2013
description:
Three types of phenotypic expression of ß-lactam resistance has been reported in MRSA: heterogeneous-, homogeneous-, and Eagle-type resistance. Heterogeneous to homogeneous (hetero-to-homo) conversion of ß-lactam resistance is postulated to be caused by a chromosomal mutation (chr*) together with mecA-gene expression. The Eagle-type resistance is a special pattern of chr* expression in the pre-MRSA strain N315 under the strong mecI-gene mediated repression of mecA gene transcription. Here, for the identification of chr*, experiments were conducted using an in-vitro derived homogeneously imipenem-resistant MRSA strain N315∆IPH5 (∆IPH5). The strain was selected with imipenem 8 mg/L from the heterogeneously imipenem-resistant MRSA strain N315∆IP (∆IP). The whole genome sequencing of ∆IPH5 revealed the presence of a unique mutation in the rpoB gene, rpoB(N967I), causing the amino-acid (AA) substitution of Asp by Ile at the 967th AA position of the RNA polymerase ß subunit. The effect of the mutation on the phenotypic change was confirmed by constructing and studying the phenotype of the strains H5rpoB(I967N), a ∆IPH5-derived strain cured of the rpoB mutation, and N315rpoB(N967I), a N315-derived strain introduced with the mutated rpoB gene. H5rpoB(I967N) regained the hetero-MRSA phenotype, and the mutant strain N315rpoB(N967I) showed an Eagle-type phenotype similar to that of N315h4. Furthermore, subsequent whole genome sequencing revealed that N315h4 also had a missense mutation in the rpoB gene rpoB(R644H). The rpoB mutations caused decreased autolysis, prolonged doubling-time, and tolerance to bactericidal concentrations of methicillin. We concluded that the certain rpoB mutations are chr* responsible for the hetero-to-homo phenotypic conversion of MRSA. We compared the gene expression profiles of the wild-type strain and rpoB mutant (N967I) using a 60mer oligo array.
privacy:
not applicable
aggregation:
instance of dataset
ID:
E-GEOD-42218
refinement:
raw
alternateIdentifiers:
42218
keywords:
functional genomics
dateModified:
05-03-2014
availability:
available
types:
gene expression
name:
Staphylococcus aureus
ID:
A-GEOD-16176
name:
NimbleGen Staphylococcus aureus 3.8K oligo array [2009_08_03_RDKK206_Saur_60mer_expr]
accessURL: https://www.ebi.ac.uk/arrayexpress/files/E-GEOD-42218/E-GEOD-42218.raw.1.zip
storedIn:
ArrayExpress
qualifier:
gzip compressed
format:
TXT
accessType:
download
authentication:
none
authorization:
none
accessURL: https://www.ebi.ac.uk/arrayexpress/files/E-GEOD-42218/E-GEOD-42218.processed.1.zip
storedIn:
ArrayExpress
qualifier:
gzip compressed
format:
TXT
accessType:
download
authentication:
none
authorization:
none
accessURL: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE42218
storedIn:
Gene Expression Omnibus
qualifier:
not compressed
format:
HTML
accessType:
landing page
primary:
true
authentication:
none
authorization:
none
abbreviation:
EBI
homePage: http://www.ebi.ac.uk/
ID:
SCR:004727
name:
European Bioinformatics Institute
homePage: https://www.ebi.ac.uk/arrayexpress/
ID:
SCR:002964
name:
ArrayExpress
Similar Datasets

Feedback?

If you are having problems using our tools, or if you would just like to send us some feedback, please post your questions on GitHub.