title: Mycoplasmas regulate the expression of heat-shock protein genes through CIRCE-HrcA interactions.
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.
authors.affiliation: Department of Life Science, Institute of Biotechnology, National Dong Hwa University, 1 University Street, Hualien, Taiwan 974, ROC.
authors.forename: Li-Jen
authors.initials: LJ
authors.lastname: Chang
authors.forename: Wei-Hsiuan
authors.initials: WH
authors.lastname: Chen
authors.forename: F Chris
authors.initials: FC
authors.lastname: Minion
authors.forename: David
authors.initials: D
authors.lastname: Shiuan
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D023281:Genomics; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D018869:Heat-Shock Response / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D045705:Mycoplasma hyopneumoniae / Q000235:genetics* / Q000502:physiology; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics* / Q000502:physiology; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D012097:Repressor Proteins; D012808:Sigma Factor; C063842:dnaK protein, E coli