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Regulation of AmtR‐controlled gene expression in Corynebacterium glutamicum : mechanism and characterization of the AmtR regulon
Author(s) -
Beckers Gabriele,
Strösser Julia,
Hildebrandt Ulrich,
Kalinowski Jörn,
Farwick Mike,
Krämer Reinhard,
Burkovski Andreas
Publication year - 2005
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2005.04855.x
Subject(s) - regulon , corynebacterium glutamicum , biology , repressor , operon , gene , biochemistry , transcriptional regulation , regulation of gene expression , glutamine synthetase , glutamine amidotransferase , transcriptome , transcription (linguistics) , transcription factor , gene expression , genetics , glutamine , amino acid , mutant , linguistics , philosophy
Summary AmtR, the master regulator of nitrogen control in Corynebacterium glutamicum , represses transcription of a number of genes during nitrogen surplus. Repression is released by an interaction of AmtR with signal transduction protein GlnK. As shown by pull‐down assays and gel retardation experiments, only adenylylated GlnK, which is present in the cells during nitrogen limitation, is able to bind to AmtR. The AmtR regulon was characterized in this study by a combination of bioinformatics, transcriptome and proteome analyses. At least 33 genes are directly controlled by the repressor protein including those encoding transporters and enzymes for ammonium assimilation ( amtA , amtB , glnA , gltBD ), urea and creatinine metabolism ( urtABCDE , ureABCEFGD , crnT , codA ), a number of biochemically uncharacterized enzymes and transport systems (NCgl1099, NCgl1100, NCgl 1915–1918) as well as signal transduction proteins ( glnD , glnK ). For the AmtR regulon, an AmtR box has been defined which comprises the sequence tttCTATN 6 AtAGat/aA. Furthermore, the transcriptional organization of AmtR‐regulated genes and operons was characterized.