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The lrp gene product regulates expression of lysU in Escherichia coli K-12

1992; American Society for Microbiology; Volume: 174; Issue: 9 Linguagem: Inglês

10.1128/jb.174.9.2779-2784.1992

1098-5530

Rong Tuan Lin, Brian R. Ernsting, Irvin N. Hirshfield, Rowena G. Matthews, Frederick C. Neidhardt, Robert L. Clark, E. B. Newman,

Bacteriophages and microbial interactions

In Escherichia coli K-12, expression of the lysU gene is regulated by the lrp gene product, as indicated by an increase in the level of lysyl-tRNA synthetase activity and LysU protein in an lrp mutant. Comparison of the patterns of protein expression visualized by two-dimensional gel electrophoresis indicated that LysU is present at higher levels in an lrp strain than in its isogenic lrp+ parent. The purified lrp gene product was shown to bind to sites upstream of the lysU gene and to protect several sites against DNase I digestion. A region extending over 100 nucleotides, between 60 and 160 nucleotides upstream from the start of the lysU coding sequence, showed altered sensitivity to DNase I digestion in the presence of the Lrp protein. The extent of protected DNA suggests a complex interaction of Lrp protein and upstream lysU DNA.