Negative autoregulation of the Rhizobium meliloti fixK gene is indirect and requires a newly identified regulator, FixT

被引:42
作者
Foussard, M [1 ]
Garnerone, AM [1 ]
Ni, F [1 ]
Soupene, E [1 ]
Boistard, P [1 ]
Batut, J [1 ]
机构
[1] INRA,CNRS,LAB BIOL MOL RELAT PLANTES MICROORGANISMES,F-31326 CASTANET TOLOSAN,FRANCE
关键词
D O I
10.1046/j.1365-2958.1997.4501814.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
fixK genes are crpl fnr homologues that have been discovered in diverse Rhizobium spp., in which they are usually essential for symbiotic nitrogen fixation, One recurrent function of fixK genes in rhizobia is to activate the transcription of operons required for respiration in the microoxic environment of the nodule,ln a similar manner to its Escherichia coli crp and fnr homologues, R. meliloti fixK regulates its own expression negatively, However, we demonstrate here that fixK negative autoregulation is not direct and, instead, involves a newly identified gene, fixT, the expression of which depends on fixK. Inactivation of fixT resulted in derepression of fixK expression under free-living microoxic conditions, Furthermore, constitutively expressed fixT strongly repressed fixK-lacZ expression in the absence of a functional fixK gene. Several lines of evidence indicate that fixT is active via its protein product FixT. FixT does not resemble any protein present in databases so far, Modules induced by a fixT mutant were Fix(+), thus demonstrating that fixT is not essential for symbiotic nitrogen fixation.
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页码:27 / 37
页数:11
相关论文
共 31 条
  • [1] OXYGEN REGULATION OF NIFA TRANSCRIPTION INVITRO
    AGRON, PG
    DITTA, GS
    HELINSKI, DR
    [J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1993, 90 (08) : 3506 - 3510
  • [2] INVITRO ACTIVITY OF THE NITROGEN-FIXATION REGULATORY PROTEIN FIXJ FROM RHIZOBIUM-MELILOTI
    BATUT, J
    SANTERO, E
    KUSTU, S
    [J]. JOURNAL OF BACTERIOLOGY, 1991, 173 (18) : 5914 - 5917
  • [3] FIXK, A GENE HOMOLOGOUS WITH FNR AND CRP FROM ESCHERICHIA-COLI, REGULATES NITROGEN-FIXATION GENES BOTH POSITIVELY AND NEGATIVELY IN RHIZOBIUM-MELILOTI
    BATUT, J
    DAVERANMINGOT, ML
    JACOBS, MDJ
    GARNERONE, AM
    KAHN, D
    [J]. EMBO JOURNAL, 1989, 8 (04) : 1279 - 1286
  • [4] Cherfils J, 1989, J Mol Recognit, V2, P114, DOI 10.1002/jmr.300020303
  • [5] Conover W. J., 1980, Practical nonparametric statistics, V2nd
  • [6] CASCADE REGULATION OF NIF GENE-EXPRESSION IN RHIZOBIUM-MELILOTI
    DAVID, M
    DAVERAN, ML
    BATUT, J
    DEDIEU, A
    DOMERGUE, O
    GHAI, J
    HERTIG, C
    BOISTARD, P
    KAHN, D
    [J]. CELL, 1988, 54 (05) : 671 - 683
  • [7] MODULAR STRUCTURE OF THE FIXL PROTEIN OF RHIZOBIUM-MELILOTI
    DEPHILIP, P
    SOUPENE, E
    BATUT, J
    BOISTARD, P
    [J]. MOLECULAR & GENERAL GENETICS, 1992, 235 (01): : 49 - 54
  • [8] PLASMIDS RELATED TO THE BROAD HOST RANGE VECTOR, PRK290, USEFUL FOR GENE CLONING AND FOR MONITORING GENE-EXPRESSION
    DITTA, G
    SCHMIDHAUSER, T
    YAKOBSON, E
    LU, P
    LIANG, XW
    FINLAY, DR
    GUINEY, D
    HELINSKI, DR
    [J]. PLASMID, 1985, 13 (02) : 149 - 153
  • [9] GENETIC-REGULATION OF NITROGEN-FIXATION IN RHIZOBIA
    FISCHER, HM
    [J]. MICROBIOLOGICAL REVIEWS, 1994, 58 (03) : 352 - 386
  • [10] GALINIER A, 1994, J BIOL CHEM, V269, P23784