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Name: | melR | |||||||||
Synonym(s): | OP00050 | |||||||||
Gene(s): | melR Genome Browser M3D Gene expression COLOMBOS | |||||||||
Note(s): | MelR binds to five target sites, sites R (+2.5), 1' (-116.5), 1 (-136.5), 2 (-174.5), and 2' (-194.5), in the melR promoter, where the less-conserved site 2' (7 of 18 bases) binds MelR most weakly Belyaeva TA,2000 MelR binding to site 2' (-194.5) occurs only in the presence of melibiose Howard VJ,2002 Based on in vivo and in vitro methods, a repression model was proposed in which four DNA-bound MelR molecules are required for optimal autorepression of the melR operon [site 2 (-174.5), site 1 (-136.5), site 1' (-116.5, and site R (+2.5)] in the absence of melibiose. This means that MelR autoregulates its own expression by binding to site +2.5 and repressing its own promoter. This repression is reinforced by upstream binding of MelR Samarasinghe S,2008. Elrobh et al. (2013) showed that efficient repression of the melR promoter by MelR requires an interaction between the proximal R (+2.5) and distal 2 (-174.5) sites and results in loop formation, as seen with another AraC member (AraC controlling the araC-araBAD intergenic regulatory region) Elrobh MS, Webster CL, Samarasinghe S, Durose D, Busby SJ,2013 In the absence of melibiose, MelR is unable to activate the melAB promoter but autoregulates its own expression by repressing the melR promoter Wade JT,2000 Melibiose triggers MelR-dependent activation of the melAB promoter and relieves MelR-dependent repression of the melR promoter Howard VJ,2002. Wade JT,2000. Tamai E,2000. Caswell R, Webster C, Busby S,1992. Belyaeva TA,2000 |
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Evidence: | [BTEI] Boundaries of transcription experimentally identified | |||||||||
Reference(s): |
[1] Bourgerie SJ., et al., 1997 [2] Caswell R., et al., 1992 [3] Michan CM., et al., 1995 |
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Promoter | ||||||||||
Name: | melRp | |||||||||
+1: | 4341650 | |||||||||
Sigma Factor: | Sigma70 Sigmulon | |||||||||
Distance from start of the gene: | 22 | |||||||||
Sequence: |
agggtgaaaaccgtgctcccactcgcagtcatcctccctcactcctgccataattctgatAttccaggaaagagagccatc -35 -10 +1 |
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Evidence: |
[ICWHO] [TIM] |
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Reference(s): |
[4] Huerta AM., et al., 2003 [5] Wade JT., et al., 2000 [6] Webster C., et al., 1987 |
Type | Transcription factor | Function | Promoter | Binding Sites | Growth Conditions | Evidence (Confirmed, Strong, Weak) | Reference(s) | |||
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LeftPos | RightPos | Central Rel-Pos | Sequence | |||||||
proximal | CRP-cyclic-AMP | activator | melRp | 4341681 | 4341702 | -41.5 | agagggtgaaAACCGTGCTCCCACTCGCAGTCatcctccctc | nd | [GEA], [AIBSCS], [APIORCISFBSCS], [BPP] | [5], [7], [8], [10], [12] |
remote | CRP-cyclic-AMP | activator | melRp | 4341795 | 4341816 | -155.5 | taaactcagaTCCTGCGTGAAGCAGCAGTAAAtctgagttta | nd | [GEA], [AIBSCS], [APIORCISFBSCS], [BPP] | [5], [7], [8], [10] |
Type | Transcription factor | Function | Promoter | Binding Sites | Growth Conditions | Evidence (Confirmed, Strong, Weak) | Reference(s) | |||
---|---|---|---|---|---|---|---|---|---|---|
LeftPos | RightPos | Central Rel-Pos | Sequence | |||||||
remote | MelR-melibiose | activator | melRp | 4341836 | 4341853 | -194.5 | tgcagaaaacCTCCGGCTTCCAGGTTGAgcattcccat | nd | [GEA], [BPP], [SM] | [5] |
Type | Transcription factor | Function | Promoter | Binding Sites | Growth Conditions | Evidence (Confirmed, Strong, Weak) | Reference(s) | |||
---|---|---|---|---|---|---|---|---|---|---|
LeftPos | RightPos | Central Rel-Pos | Sequence | |||||||
proximal | MelR | repressor | melRp | 4341640 | 4341657 | 2.5 | cctgccataaTTCTGATATTCCAGGAAAgagagccatc | nd | [GEA], [APIORCISFBSCS], [BPP], [SM] | [7], [8], [9] |
remote | MelR-melibiose | repressor | melRp | 4341758 | 4341775 | -116.5 | atgggaataaATTACCTGAAAAGCAGAGttttcggcct | nd | [GEA], [APIORCISFBSCS], [BPP] | [5], [7], [9], [11] |
remote | MelR-melibiose | repressor | melRp | 4341778 | 4341795 | -136.5 | gcagcagtaaATCTGAGTTTATGGGAATaaattacctg | nd | [GEA], [APIORCISFBSCS], [BPP] | [5], [7], [9], [11] |
remote | MelR | repressor | melRp | 4341816 | 4341833 | -174.5 | caggttgagcATTCCCATAAACTCAGATcctgcgtgaa | nd | [GEA], [BPP] | [5], [7], [8], [9] |
Reference(s) |
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