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Results

Binding Sites for RNA Polymerase and NRI in the g/nA Promoter Region We examined the ability of core RNA polymerase, a54, NR,, NRrr, and various combinations of these proteins to protect sequences in the g/nA promoter region from cleavage by DNAase I. Previous results from other laboratories using the g/nA promoter region from related bacteria had indicated that NR, binds with high affinity to two sites at positions-147 to-132 (site 1) and-115 to-100 (site 2) relative to the site of transcription initiation (Ames and Nikaido, 1985; Hawkes et al., 1985) and with a lower affinity to three additional sites located between glnAp2 and site 2 (Hirschman et al., 1985). In addition; partially purified EoM from Salmonella typhimurium has been reported to protect the glnAp2 Ntr-promoter consensus sequence in the absence of NR, and NR,,(Kustu et al., 1986). Our purpose in these experiments was to examine the …