Corynebacterium glutamicum sigmaE is involved in responses to cell surface stresses and its activity is controlled by the anti-sigma factor CseE.
In this study, we demonstrate that sigma(E), an alternative sigma factor of Corynebacterium glutamicum, is involved in cell surface stresses. Cells in which the sigE gene was deleted evidenced increased sensitivity to magnesium deficiency, as well as to SDS, lysozymes, EDTA and heat. We utilized physiological analyses to show that the downstream gene, designated cseE, encodes an anti-sigma factor. The retarded growth of the cseE mutant cells under ordinary growth conditions could be recovered by an additional deletion of sigE encoding sigma(E). Under stress conditions, the phenotype of the cseE-overexpressing cells mimicked that of the sigE mutant. The sigE and cseE genes were transcribed into a single transcript, and gene transcription was stimulated by heat. The SigE and CseE proteins interacted physically in vitro, in the form of glutathione S-transferase (GST) and maltose binding protein (MBP) fusion proteins, respectively. 2D-PAGE analysis of the wild-type and mutant crude extracts showed that the sigE mutant failed to synthesize a 34 kDa polypeptide that was normally induced in wild-type cells grown under heat (or SDS)-stressed conditions. The protein turned out to be expressed from ORF NCgl1070 and showed similarity to methyltransferases which may confer resistance to antibiotics. Accordingly, the sigE mutant evidenced extreme sensitivity to antibiotics, including nalidixic acid, penicillin and vancomycin. Finally, we present a discussion of the possible role of the sigE and cseE genes in the acclimation of C. glutamicum to cell surface stress conditions.
Park
Soo-Dong
SD
Graduate School of Biotechnology, Korea University, Anam-Dong, Sungbuk-Ku, Seoul 136-701, Republic of Korea.
Youn
Jung-Won
JW
Institute of Biotechnology 1, Heinrich Heine University, Research Center Jülich, D-52425 Jülich, Germany.
Kim
Young-Joon
YJ
Department of Biotechnology and Bioinformatics, Korea University, Jochiwon, Chungnam 339-700, Republic of Korea.
Lee
Seok-Myung
SM
Department of Biotechnology and Bioinformatics, Korea University, Jochiwon, Chungnam 339-700, Republic of Korea.
Kim
Younhee
Y
Department of Oriental Medicine, Semyung University, Checheon, Chungbuk 390-230, Republic of Korea.
Lee
Heung-Shick
HS
Department of Biotechnology and Bioinformatics, Korea University, Jochiwon, Chungnam 339-700, Republic of Korea.
D000222:Adaptation, Physiological; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D048230:Corynebacterium glutamicum / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D004492:Edetic Acid / Q000494:pharmacology; D015180:Electrophoresis, Gel, Two-Dimensional; D017353:Gene Deletion; D020869:Gene Expression Profiling; D006358:Hot Temperature; D008274:Magnesium / Q000378:metabolism; D009113:Muramidase / Q000494:pharmacology; D016254:Mutagenesis, Insertional; D011485:Protein Binding; D020543:Proteome / Q000032:analysis; D012329:RNA, Bacterial / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D020543:Proteome; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012808:Sigma Factor; D014157:Transcription Factors; C063202:sporulation-specific sigma factors; D012967:Sodium Dodecyl Sulfate; D004492:Edetic Acid; D009113:Muramidase; D008274:Magnesium