The ratio between CcdA and CcdB modulates the transcriptional repression of the ccd poison-antidote system

被引:124
作者
Afif, H [1 ]
Allali, N [1 ]
Couturier, M [1 ]
Van Melderen, L [1 ]
机构
[1] Free Univ Brussels, Inst Biol & Med Mol, Lab Genet Procaryotes, B-6041 Gosselies, Belgium
关键词
D O I
10.1046/j.1365-2958.2001.02492.x
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The ccd operon of the F plasmid encodes CcdB, a toxin targeting the essential gyrase of Escherichia coli, and CcdA, the unstable antidote that interacts with CcdB to neutralize its toxicity. Although work from our group and others has established that CcdA and CcdB are required for transcriptional repression of the operon, the underlying mechanism remains unclear. The results presented here indicate that, although CcdA is the DNA-binding element of the CcdA-CcdB complex, the stoichiometry of the two proteins determines whether or not the complex binds to the ccd operator-promoter region. Using electrophoretic mobility shift assays, we show that a (CcdA)2-(CcdB)2 complex binds DNA. The addition of extra CcdB to that protein-DNA complex completely abolishes DNA retardation. Based on these results, we propose a model in which the ratio between CcdA and CcdB regulates the repression state of the ccd operon. When the level of CcdA is superior or equal to that of CcdB, repression results. In contrast, derepression occurs when CcdB is in excess of CcdA, By ensuring an antidote-toxin ratio greater than one, this mechanism could prevent the harmful effect of CcdB in plasmid-containing bacteria.
引用
收藏
页码:73 / 82
页数:10
相关论文
共 30 条
[1]   Interactions of CcdB with DNA gyrase - Inactivation of GyrA, poisoning of the gyrase-DNA complex, and the antidote action of CcdA [J].
Bahassi, EM ;
O'Dea, MH ;
Allali, N ;
Messens, J ;
Gellert, M ;
Couturier, M .
JOURNAL OF BIOLOGICAL CHEMISTRY, 1999, 274 (16) :10936-10944
[2]   CELL KILLING BY THE F-PLASMID CCDB PROTEIN INVOLVES POISONING OF DNA-TOPOISOMERASE-II COMPLEXES [J].
BERNARD, P ;
COUTURIER, M .
JOURNAL OF MOLECULAR BIOLOGY, 1992, 226 (03) :735-745
[3]   THE F-PLASMID CCDB PROTEIN INDUCES EFFICIENT ATP-DEPENDENT DNA CLEAVAGE BY GYRASE [J].
BERNARD, P ;
KEZDY, KE ;
VANMELDEREN, L ;
STEYAERT, J ;
WYNS, L ;
PATO, ML ;
HIGGINS, PN ;
COUTURIER, M .
JOURNAL OF MOLECULAR BIOLOGY, 1993, 234 (03) :534-541
[4]   THE 41 CARBOXY-TERMINAL RESIDUES OF THE MINIF PLASMID CCDA PROTEIN ARE SUFFICIENT TO ANTAGONIZE THE KILLER ACTIVITY OF THE CCDB PROTEIN [J].
BERNARD, P ;
COUTURIER, M .
MOLECULAR & GENERAL GENETICS, 1991, 226 (1-2) :297-304
[5]   REGULATION OF RIBOSOMAL-RNA PROMOTERS WITH A SYNTHETIC LAC OPERATOR [J].
BROSIUS, J ;
HOLY, A .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES, 1984, 81 (22) :6929-6933
[6]   Bacterial death by DNA gyrase poisoning [J].
Couturier, M ;
Bahassi, E ;
Van Melderen, L .
TRENDS IN MICROBIOLOGY, 1998, 6 (07) :269-275
[7]   The thermodynamic stability of the proteins of the ccd plasmid addiction system [J].
Dao-Thi, MH ;
Messens, J ;
Wyns, L ;
Backmann, J .
JOURNAL OF MOLECULAR BIOLOGY, 2000, 299 (05) :1373-1386
[8]   Plasmid copy-number control and better-than-random segregation genes of pSM19035 share a common regulator [J].
de la Hoz, AB ;
Ayora, S ;
Sitkiewicz, I ;
Fernández, S ;
Pankiewicz, R ;
Alonso, JC ;
Ceglowski, P .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2000, 97 (02) :728-733
[9]   AUTO-REGULATION OF THE CCD OPERON IN THE F-PLASMID [J].
DEFEYTER, R ;
WALLACE, C ;
LANE, D .
MOLECULAR & GENERAL GENETICS, 1989, 218 (03) :481-486
[10]   Addiction modules and programmed cell death and antideath in bacterial cultures [J].
Engelberg-Kulka, H ;
Glaser, G .
ANNUAL REVIEW OF MICROBIOLOGY, 1999, 53 :43-70