Abstract
Mycoplasmas in general are rarely exposed to severe environmental changes except during its colonization and infection processes. Genomic analysis indicates that Mycoplasma hyopneumoniae possesses the genes of a single sigma factor and the HrcA repressor of negative regulation of the heat-shock response. A perfect inverted repeat sequence (5'-CTGGCACTT-N(9)-AAGTGCCAA-3') upstream of the DnaK gene has also been identified. In the present study, we demonstrate the functionality of HrcA-CIRCE interactions using the gel electrophoretic mobility shift assay. The presence of the unique sigma factor, HrcA repressor, and the CIRCE-like sequences reveals that mycoplasmal species may all use the negative regulatory mechanism in the heat-shock response. It is conceivable that mycoplasmas may have evolved a single HrcA repressor-based mechanism which might be the most simple and economical way of controlling HSP gene expression.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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Base Sequence
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Electrophoretic Mobility Shift Assay
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Escherichia coli Proteins / genetics
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Escherichia coli Proteins / metabolism
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Gene Expression Regulation, Bacterial*
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Genes, Regulator*
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Genomics
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HSP70 Heat-Shock Proteins / genetics
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HSP70 Heat-Shock Proteins / metabolism
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Heat-Shock Proteins / genetics*
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Heat-Shock Proteins / metabolism
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Heat-Shock Response / genetics
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Heat-Shock Response / physiology
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Molecular Sequence Data
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Mycoplasma hyopneumoniae / genetics*
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Mycoplasma hyopneumoniae / physiology
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Regulatory Sequences, Nucleic Acid / genetics*
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Regulatory Sequences, Nucleic Acid / physiology
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Repressor Proteins / genetics
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Repressor Proteins / metabolism*
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Sigma Factor / genetics
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Sigma Factor / metabolism
Substances
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Bacterial Proteins
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DNA-Binding Proteins
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Escherichia coli Proteins
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HSP70 Heat-Shock Proteins
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Heat-Shock Proteins
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Repressor Proteins
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Sigma Factor
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dnaK protein, E coli