A celR mutation affecting transcription of cellulase genes in Thermobifida fusca.
Biosynthesis of extracellular cellulases in the cellulose-degrading actinomycete Thermobifida fusca is controlled by a transcriptional regulator, CelR, and cellobiose, which acts as an inducer interfering with the CelR-DNA interaction. We report the identification and characterization of a mutation in the celR gene that changes Ala(55) in the hinge helix of CelR to Thr. The wild-type and mutant celR genes were cloned in Escherichia coli, and their protein products were characterized. The CelR mutant protein bound DNA more weakly than the wild-type protein and formed a less stable complex with DNA in the presence of cellobiose. The results of Western analysis and gel retardation experiments suggest that CelR is produced constitutively and its DNA-binding activity is regulated through posttranslational modification.
Spiridonov
N A
NA
Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.
Wilson
D B
DB
D000192:Actinomycetales / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins; D002475:Cellobiose / Q000378:metabolism; D002480:Cellulase / Q000235:genetics* / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D009154:Mutation; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
D001426:Bacterial Proteins; C119069:CelR protein, bacteria; D005656:Fungal Proteins; D011994:Recombinant Proteins; D012097:Repressor Proteins; D002475:Cellobiose; D002480:Cellulase