Gel retardation assays indicated that Lrp binds a DNA region upstream of the traJ promoter .
Because the 84 bp fragments both contain the region homologous to the Lrp binding site , these observations provided evidence that Lrp binds to the UAS of traJ .
Because the 313 bp both contain the region homologous to the Lrp binding site , these observations provided evidence that Lrp binds to the UAS of traJ .
Retardation of the DNA fragment under study is clearly observed , thereby confirming that Lrp binds the traJ UAS .
We thus propose that binding of Lrp to the UAS upstream of traJ activates traJ transcription .
We thus propose that binding of Lrp to the UAS upstream of traJ activates traJ transcription .
In addition , Lrp controls the expression of the virulence plasmid traJ gene .
Lrp-regulated genes in Salmonella include fimZ , for type 1 fimbria expression ( 67 ) ; ilvIH , for branched amino-acid biosynthesis ( 93 ) ; hisJ , for D-histidine utilization ( 44 ) ; traJ , for conjugal transfer of virulence plasmid pSLT ( 13 ) ; and pef , for pSLT plasmid-encoded fimbriae ( 74 ) .