Mutations in the araC gene of Salmonella typhimurium LT2 which affect both activator and auto-regulatory functions of the AraC protein.
The araC gene encodes a regulatory protein, AraC, that acts as both an activator and a repressor of transcription of the genes involved in the transport and catabolism of L-arabinose in Salmonella typhimurium LT2. Five araC mutants which have altered regulatory properties were characterized. All are point mutations which would result in amino acid substitutions near the C terminus of AraC. Each mutation results in altered activator and auto-regulatory AraC function in vivo. In vitro DNA-binding assays showed that three mutant AraC have measurable lowered affinity for ara controlling site DNA. The data are consistent with a model in which there is a DNA-binding domain in the C terminus of AraC which functions in both activation and repression.
Clarke
P
P
Department of Microbiology, University of California, Los Angeles 90024.
Lee
J H
JH
Burke
K
K
Wilcox
G
G
D000483:Alleles; D000595:Amino Acid Sequence; D051777:AraC Transcription Factor; D001089:Arabinose / Q000378:metabolism; D001426:Bacterial Proteins; D001665:Binding Sites; D004271:DNA, Fungal / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D006706:Homeostasis; D015151:Immunoblotting; D008969:Molecular Sequence Data; D009154:Mutation; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D012486:Salmonella typhimurium / Q000235:genetics*; D014157:Transcription Factors
D051777:AraC Transcription Factor; D001426:Bacterial Proteins; D004271:DNA, Fungal; D012097:Repressor Proteins; D014157:Transcription Factors; D001089:Arabinose