The various strategies within the TyrR regulation of Escherichia coli to modulate gene expression.
The TyrR Regulon of Escherichia coli comprises eight transcription units whose expression is modulated by the TyrR protein. This protein, which is normally a homodimer in solution, can self-associate to form a hexamer, bind with high affinity to specific DNA sequences (TyrR boxes) and interact with the alpha subunit of the RNA polymerase. These various reactions are influenced by the abundance of one or more of the aromatic amino acids, tyrosine, phenylalanine or tryptophan and by the specific location and sequence of the TyrR boxes associated with each transcription unit. This review describes how these activities can be combined in different ways to produce a variety of responses to varying levels of the three aromatic amino acids.
Pittard
J
J
Department of Microbiology, University of Melbourne, Victoria, Australia.
D000595:Amino Acid Sequence; D026905:Amino Acid Transport Systems; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D010649:Phenylalanine / Q000378:metabolism; D011401:Promoter Regions, Genetic; D018085:Regulon; D012097:Repressor Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D014364:Tryptophan / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
D026905:Amino Acid Transport Systems; C063201:AroP protein, E coli; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C069256:TyrR protein, E coli; D014443:Tyrosine; D010649:Phenylalanine; D014364:Tryptophan; D012321:DNA-Directed RNA Polymerases