Disease relevance of melR

• The Escherichia coli melR gene encodes MelR protein which is a member of the AraC/XylS family of bacterial transcription activators [1].

High impact information on melR

• The function of MelR was investigated by making a targeted deletion in the melR gene of the Escherichia coli chromosome [1].
• By altering the helical phasing between a CRP binding site and the E. coli melR promoter we have mapped a DNA sequence-directed bend in the downstream region of the promoter [2].
• We have transferred a number of cassette FNR-binding sequences from the nirB promoter to the unrelated melR promoter [3].
• The insertion of FNR-binding sequences at the melR promoter is sufficient to confer fnr-dependency on expression [3].
• Supporting evidence for this is provided by the isolation of substitutions in MelR that block melibiose-dependent activation of the melAB promoter while not changing melibiose-independent repression of the melR promoter [4].

Chemical compound and disease context of melR

• Mutational analysis of the Escherichia coli melR gene suggests a two-state concerted model to explain transcriptional activation and repression in the melibiose operon [4].

Biological context of melR

• The nucleotide sequence covering the divergent promoters and the melR gene is reported [5].
• Crude extracts, made from Escherichia coli cells carrying a plasmid in which the melR gene was expressed from the galP2 promoter, were used as a source of MelR protein [6].
• Expression of the melR gene is required for melibiose-dependent stimulation of transcription initiation at the promoter of the melAB operon [7].
• We have constructed a series of artificial FNR-dependent promoters, based on the melR promoter, in which a consensus FNR binding site was centered at position -41.5 relative to the transcription start site [8].

Associations of melR with chemical compounds

• One promoter is responsible for the expression of the melR gene, that is essential for melibiose-dependent stimulation of the second promoter [5].

Other interactions of melR

• To gain more insight into this regulation, beta-galactosidase activity from a plasmid carrying the lacZ gene fused to the Escherichia coli melR promoter with the consensus FNR-binding (FF) site was examined [9].

Analytical, diagnostic and therapeutic context of melR

• Gel retardation assays and DNAse I footprinting show that human TFIID binds to the melR promoter - 10 region [2].

References