A combination of metabolome and transcriptome analyses reveals new targets of the Corynebacterium glutamicum nitrogen regulator AmtR.
The effects of a deletion of the amtR gene, encoding the master regulator of nitrogen control in Corynebacterium glutamicum, were investigated by metabolome and transcriptome analyses. Compared to the wild type, different metabolite patterns were observed in respect to glycolysis, pentose phosphate pathway, citric acid cycle, and most amino acid pools. Not all of these alterations could be attributed to changes at the level of mRNA and must be caused by posttranscriptional regulatory processes. However, subsequently carried out transcriptome analyses, which were confirmed by gel retardation experiments, revealed two new targets of AmtR, the dapD gene, encoding succinylase involved in m-diaminopimelate synthesis, and the mez gene, coding for malic enzyme. The regulation of dapD connects the AmtR-dependent nitrogen control with l-lysine biosynthesis, the regulation of mez with carbon metabolism. An increased l-glutamine pool in the amtR mutant compared to the wild type was correlated with deregulated expression of the AmtR-regulated glnA gene and an increased glutamine synthetase activity. The glutamate pool was decreased in the mutant and also glutamate excretion was impaired.
Buchinger
Sebastian
S
Institut für Biochemie, Universität zu Köln, Cologne, Germany.
Strösser
Julia
J
Rehm
Nadine
N
Hänssler
Eva
E
Hans
Stephan
S
Bathe
Brigitte
B
Schomburg
Dietmar
D
Krämer
Reinhard
R
Burkovski
Andreas
A
D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D048230:Corynebacterium glutamicum / Q000235:genetics* / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D008401:Gas Chromatography-Mass Spectrometry; D017353:Gene Deletion; D020869:Gene Expression Profiling; D005974:Glutamate-Ammonia Ligase / Q000235:genetics / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D055432:Metabolomics; D008969:Molecular Sequence Data; D012323:RNA Processing, Post-Transcriptional; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism
C414398:AmtR protein, Corynebacterium glutamicum; D001426:Bacterial Proteins; D012097:Repressor Proteins; D018698:Glutamic Acid; D000217:Acyltransferases; C040777:succinyl-CoA-tetrahydrodipicolinate N-succinyltransferase; C081173:glutamine synthetase I; D005974:Glutamate-Ammonia Ligase