title: HrcA is a negative regulator of the dnaK and groESL operons of Streptococcus pyogenes.
abstract: The genome of Streptococcus pyogenes, an important human pathogen, encodes homologs of the principal bacterial heat shock proteins DnaK and GroES, -EL, as well as HrcA, a negative regulator of dnaK and groESL expression in other Gram-positive bacteria. Using nuclease protection assays to measure dnaK/groESL mRNA abundance and a "non-polar" insertion to disrupt hrcA, we demonstrate that heat shock triggers a 4- to 8-fold increase in dnaK and groESL-specific mRNAs within 5 min of the temperature shift and that HrcA is a negative regulator of S. pyogenes dnaK/groESL mRNA abundance in unstressed S. pyogenes. Although the loss of HrcA elevated dnaK and groESL mRNA levels under non-heat shock conditions, the relative abundance of these RNAs increased further in heat shocked S. pyogenes, suggesting an additional element contributing to their synthesis or stability.
authors.affiliation: Department of Microbiology and Immunology MC7758, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229-3900, USA.
authors.forename: Robyn
authors.initials: R
authors.lastname: Woodbury
authors.forename: W G
authors.initials: WG
authors.lastname: Haldenwang
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018833:Chaperonins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009876:Operon; D012329:RNA, Bacterial / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D013297:Streptococcus pyogenes / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C097970:GroESL protein, Bacteria; D018840:HSP70 Heat-Shock Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012097:Repressor Proteins; D018833:Chaperonins; C063842:dnaK protein, E coli