The major cold shock gene, cspA, is involved in the susceptibility of Staphylococcus aureus to an antimicrobial peptide of human cathepsin G.
A Tn551 insertional library of Staphylococcus aureus strain ISP479 was challenged with an antimicrobial peptide (CG 117-136) derived from human neutrophil cathepsin G (CG). After repeated selection and screening of surviving colonies, a mutant was identified that expressed increased resistance to CG 117-136. Southern hybridization analysis revealed that the Tn551 insert in this mutant (SK1) was carried on a 10.6-kb EcoRI chromosomal DNA fragment. Subsequent physical mapping of this Tn551 insert revealed that it was positioned between a putative promoter sequence and the translational start codon of the cspA gene, which encodes a protein (CspA) highly similar to the major cold shock proteins CspA and CspB of Escherichia coli and Bacillus subtilis, respectively. This Tn551 insertion as well as a separate deletion-insertion mutation in cspA decreased the capacity of S. aureus to respond to the stress of cold shock and increased resistance to CG 117-136. The results indicate for the first time that a physiologic link exists between bacterial susceptibility to an antimicrobial peptide and a stress response system.
Katzif
Samuel
S
Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
Danavall
Damien
D
Bowers
Samera
S
Balthazar
Jacqueline T
JT
Shafer
William M
WM
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000494:pharmacology; D001483:Base Sequence; D056649:Cathepsin G; D002403:Cathepsins / Q000494:pharmacology*; D003080:Cold Temperature; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D006801:Humans; D066298:In Vitro Techniques; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010446:Peptide Fragments / Q000494:pharmacology; D011506:Proteins / Q000494:pharmacology*; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases; D012808:Sigma Factor / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development; D014158:Transcription, Genetic
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C102462:CG 117136; D004269:DNA, Bacterial; D036341:Intercellular Signaling Peptides and Proteins; D010446:Peptide Fragments; D011506:Proteins; C079011:SigB protein, Bacteria; D012808:Sigma Factor; C062260:cold shock protein CS7.4, Bacteria; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G