Role of Acinetobacter baylyi Crc in catabolite repression of enzymes for aromatic compound catabolism.
Here, we describe for the first time the Crc (catabolite repression control) protein from the soil bacterium Acinetobacter baylyi. Expression of A. baylyi crc varied according to the growth conditions. A strain with a disrupted crc gene showed the same growth as the wild type on a number of carbon sources. Carbon catabolite repression by acetate and succinate of protocatechuate 3,4-dioxygenase, the key enzyme of protocatechuate breakdown, was strongly reduced in the crc strain, whereas in the wild-type strain it underwent strong catabolite repression. This strong effect was not based on transcriptional regulation because the transcription pattern of the pca-qui operon (encoding protocatechuate 3,4-dioxygenase) did not reflect the derepression in the absence of Crc. pca-qui transcript abundance was slightly increased in the crc strain. Lack of Crc dramatically increased the mRNA stability of the pca-qui transcript (up to 14-fold), whereas two other transcripts (pobA and catA) remained unaffected. p-Hydroxybenzoate hydroxylase activity, encoded by pobA, was not significantly different in the absence of Crc, as protocatechuate 3,4-dioxygenase was. It is proposed that A. baylyi Crc is involved in the determination of the transcript stability of the pca-qui operon and thereby effects catabolite repression.
Zimmermann
Tina
T
Institute of Microbiology and Biotechnology, University of Ulm, D-89069 Ulm, Germany. ulrike.gerischer@uni-ulm.de
Sorg
Tobias
T
Siehler
Simone Yasmin
SY
Gerischer
Ulrike
U
D015109:4-Hydroxybenzoate-3-Monooxygenase / Q000096:biosynthesis; D019342:Acetic Acid / Q000378:metabolism; D000150:Acinetobacter / Q000378:metabolism / Q000502:physiology*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D002244:Carbon / Q000378:metabolism; D004794:Enzyme Repression; D004798:Enzymes / Q000096:biosynthesis; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006841:Hydrocarbons, Aromatic / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D011520:Protocatechuate-3,4-Dioxygenase / Q000096:biosynthesis; D020871:RNA Stability; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D016415:Sequence Alignment; D019802:Succinic Acid / Q000378:metabolism; D056968:Lac Repressors
D015109:4-Hydroxybenzoate-3-Monooxygenase; D019342:Acetic Acid; D001426:Bacterial Proteins; D002244:Carbon; D004798:Enzymes; D006841:Hydrocarbons, Aromatic; D011520:Protocatechuate-3,4-Dioxygenase; D012097:Repressor Proteins; D019802:Succinic Acid; C068837:FruR protein, Bacteria; D056968:Lac Repressors