title: Role of Acinetobacter baylyi Crc in catabolite repression of enzymes for aromatic compound catabolism.
abstract: 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.
authors.affiliation: Institute of Microbiology and Biotechnology, University of Ulm, D-89069 Ulm, Germany. ulrike.gerischer@uni-ulm.de
authors.forename: Tina
authors.initials: T
authors.lastname: Zimmermann
authors.forename: Tobias
authors.initials: T
authors.lastname: Sorg
authors.forename: Simone Yasmin
authors.initials: SY
authors.lastname: Siehler
authors.forename: Ulrike
authors.initials: U
authors.lastname: Gerischer
mesh_terms: 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
chemical_list: 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