Characterization of the tol-pal region of Escherichia coli K-12: translational control of tolR expression by TolQ and identification of a new open reading frame downstream of pal encoding a periplasmic protein.
The TolQ, TolR, TolA, TolB, and Pal proteins appear to function in maintaining the integrity of the outer membrane, as well as facilitating the uptake of the group A colicins and the DNA of the infecting filamentous bacteriophages. Sequence data showed that these genes are clustered in a 6-kb segment of DNA with the gene order orf1 tolQ tolR tolA tolB pal orf2 (a newly identified open reading frame encoding a 29-kD9 protein). Like those containing orf1, bacteria containing an insertion mutation in this gene showed no obvious phenotype. Analysis of beta-galactosidase activity from fusion constructs in which the lac operon was fused to various genes in the cluster showed that the genes in this region constitute two separate operons: orf1 tolQRA and tolB pal orf2. In the orf1 tolQRA operon, translation of MR was dependent on translation of the upstream tolQ region. Consistent with this result, no functional ribosome-binding site for TolR synthesis was detected.
Vianney
A
A
Laboratoire de Microbiologie et Génétique Moléculaire, Centre National de la Recherche Scientifique, Université Claude Bernard Lyon I, France.
Muller
M M
MM
Clavel
T
T
Lazzaroni
J C
JC
Portalier
R
R
Webster
R E
RE
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016366:Open Reading Frames; D009876:Operon; D014176:Protein Biosynthesis; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; C060792:tolQ protein, E coli; C060794:tolR protein, E coli