Regulation of aroP expression by tyrR gene in Escherichia coli.
tyrR gene encodes a global regulatory protein (TyrR), which plays an important role in the transcriptional regulation of eight transcription units (including tyrR gene itself) whose protein products catalyze key steps in aromatic amino acid biosynthesis and/or transport. The aroP gene encodes an integral membrane protein (AroP) that transports aromatic amino acids through the cell membrane. The transcription of aroP was reported to be repressed by TyrR. In this work, aroP(p) (aroP gene carrying its own promoter), aroP (aroP gene without promoter) and tyrR genes were amplified by PCR from genomic DNA of E. coli K12 and introduced into E. coli WT5. The expression of aroP and tyrR were detected and the activities of AroP and TyrR were determined. The introduction of either aroP(p) or aroP elevated the strain's transport activity by 1.40 or 1.46-fold respectively. Transformant carrying tyrR gene showed an ATPase activity 1.69-fold compared with the control. When the genes were linked in tandem and co-expressed in a plasmid, the relative AroP transport activity of the strain harboring aroP(p) -tyrR (0.95) was significantly lower than that of aroP-tyrR (1.31). The results indicated that TyrR might be able to reduce the expression of aroP gene by binding with the aroP promoter region in E.coli.
Wang
Jian-Gang
JG
Department of Microbiology, School of Life Sciences, Fudan University, Shanghai 200433, China.
Fan
Chang-Sheng
CS
Wu
Yong-Qing
YQ
Jin
Rui-Liang
RL
Liu
Dong-Xin
DX
Shang
Liang
L
Jiang
Pei-Hong
PH
D000251:Adenosine Triphosphatases / Q000378:metabolism; D026905:Amino Acid Transport Systems; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D010649:Phenylalanine / Q000096:biosynthesis / Q000493:pharmacokinetics; D010957:Plasmids / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*
D026905:Amino Acid Transport Systems; C063201:AroP protein, E coli; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; C069256:TyrR protein, E coli; D010649:Phenylalanine; D000251:Adenosine Triphosphatases