|Gene:||lrhA||Accession Numbers: EG12123 (EcoCyc), b2289, ECK2283|
LrhA, "LysR homologue A," regulates the transcription of genes involved in the synthesis of type 1 fimbriae [Blumer05]. Indirectly, this protein also regulates the transcription of several genes involved in motility, chemotaxis, and flagellum synthesis by directly controlling the expression of the master regulator FlhDC [Lehnen02].
On the other hand, LrhA also regulates negatively and partially the translation of rpoS through two mechanisms, one of which is RprA dependent and the other one is RprA independent. RprA is a small RNA that regulates positively the translation of rpoS. Both mechanisms of regulation require the presence of the sRNA chaperone Hfq; therefore, it was suggested that another small RNA , in addition to RprA , that regulates rpoS translation is regulated by LrhA [Peterson06].
LrhA is a protein that belongs to the LysR family and, like the members of this family, LrhA contains three different domains: an N-terminal helix-turn-helix domain for DNA binding, a coinducer recognition domain in the center of the protein, and a C-terminal domain that contains a cluster of four cysteine and two histidine residues [Bongaerts95]. The activity of most members of this family is controlled by small molecules; however, the effector of LrhA was not known until now [Lehnen02]. LrhA has high degree of homology to HexA from Erwinia carotovora (64% identity ) and PecT from Erwinia chrysanthemi (61% identity) [Harris98a, Surgey96].
LrhA appears to recognize and bind to a partial palindromic DNA sequence of 13 bp that shows low similarity to the general consensus for LysR family members [Lehnen02].
The lrhA gene is transcribed alone, and it is under positive autoregulation by LrhA. Unlike the majority of LysR-type regulators, LrhA does not regulate the expression of adjacent genes to lrhA [Lehnen02]. The expression of lrhA is repressed by the RcsCDB phosphorelay system and by the DNA motor protein FtsK [Peterson06].
|Map Position: [2,403,725 <- 2,404,663] (51.81 centisomes, 187°)||Length: 939 bp / 312 aa|
Molecular Weight of Polypeptide: 34.594 kD (from nucleotide sequence)
Unification Links: ASAP:ABE-0007555 , CGSC:32685 , EchoBASE:EB2044 , EcoGene:EG12123 , EcoliWiki:b2289 , ModBase:P36771 , OU-Microarray:b2289 , PortEco:lrhA , Protein Model Portal:P36771 , RefSeq:NP_416792 , RegulonDB:EG12123 , SMR:P36771 , String:511145.b2289 , UniProt:P36771
Relationship Links: InterPro:IN-FAMILY:IPR000847 , InterPro:IN-FAMILY:IPR005119 , InterPro:IN-FAMILY:IPR011991 , Pfam:IN-FAMILY:PF00126 , Pfam:IN-FAMILY:PF03466 , Prints:IN-FAMILY:PR00039 , Prosite:IN-FAMILY:PS50931
In Paralogous Gene Group: 6 (42 members)
|Biological Process:||GO:0006351 - transcription, DNA-templated
[UniProtGOA11a, Lehnen02, Bongaerts95, Gibson99]
GO:0006355 - regulation of transcription, DNA-templated [UniProtGOA11a, Gaudet10, GOA01a]
|Molecular Function:||GO:0043565 - sequence-specific DNA binding
GO:0003677 - DNA binding [UniProtGOA11a]
GO:0003700 - sequence-specific DNA binding transcription factor activity [Gaudet10, GOA01a]
|Cellular Component:||GO:0005737 - cytoplasm
GO:0005829 - cytosol [DiazMejia09]
|MultiFun Terms:||information transfer → RNA related → Transcription related|
|regulation → genetic unit regulated → operon|
|regulation → type of regulation → transcriptional level → repressor|
DNA binding site length: 15 base-pairs
Symmetry: Inverted Repeat
|Growth Medium||Growth?||T (°C)||O2||pH||Osm/L||Growth Observations|
|LB enriched||Yes||37||Aerobic||6.95||Yes [Gerdes03, Comment 1]|
|LB Lennox||Yes||37||Aerobic||7||Yes [Baba06, Comment 2]|
|M9 medium with 1% glycerol||Yes||37||Aerobic||7.2||0.35||Yes [Joyce06, Comment 3]|
|MOPS medium with 0.4% glucose||Yes||37||Aerobic||7.2||0.22||Yes [Baba06, Comment 2]|
|Conserved-Region||11 -> 68|
|DNA-Binding-Region||28 -> 47|
|Sequence-Conflict||291 -> 312|
10/20/97 Gene b2289 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG12123; confirmed by SwissProt match.
Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554
Blumer05: Blumer C, Kleefeld A, Lehnen D, Heintz M, Dobrindt U, Nagy G, Michaelis K, Emody L, Polen T, Rachel R, Wendisch VF, Unden G (2005). "Regulation of type 1 fimbriae synthesis and biofilm formation by the transcriptional regulator LrhA of Escherichia coli." Microbiology 151(Pt 10);3287-98. PMID: 16207912
Bongaerts95: Bongaerts J, Zoske S, Weidner U, Unden G (1995). "Transcriptional regulation of the proton translocating NADH dehydrogenase genes (nuoA-N) of Escherichia coli by electron acceptors, electron donors and gene regulators." Mol Microbiol 16(3);521-34. PMID: 7565112
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
Gerdes03: Gerdes SY, Scholle MD, Campbell JW, Balazsi G, Ravasz E, Daugherty MD, Somera AL, Kyrpides NC, Anderson I, Gelfand MS, Bhattacharya A, Kapatral V, D'Souza M, Baev MV, Grechkin Y, Mseeh F, Fonstein MY, Overbeek R, Barabasi AL, Oltvai ZN, Osterman AL (2003). "Experimental determination and system level analysis of essential genes in Escherichia coli MG1655." J Bacteriol 185(19);5673-84. PMID: 13129938
Harris98a: Harris SJ, Shih YL, Bentley SD, Salmond GP (1998). "The hexA gene of Erwinia carotovora encodes a LysR homologue and regulates motility and the expression of multiple virulence determinants." Mol Microbiol 28(4);705-17. PMID: 9643539
Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394
Lehnen02: Lehnen D, Blumer C, Polen T, Wackwitz B, Wendisch VF, Unden G (2002). "LrhA as a new transcriptional key regulator of flagella, motility and chemotaxis genes in Escherichia coli." Mol Microbiol 2002;45(2);521-32. PMID: 12123461
Peterson06: Peterson CN, Carabetta VJ, Chowdhury T, Silhavy TJ (2006). "LrhA regulates rpoS translation in response to the Rcs phosphorelay system in Escherichia coli." J Bacteriol 188(9);3175-81. PMID: 16621809
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