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hha hemolysin expression-modulating protein Hha [ Escherichia coli str. K-12 substr. MG1655 ]

Gene ID: 945098, updated on 4-Feb-2026
Official Symbol
hha
Official Full Name
hemolysin expression-modulating protein Hha
Primary source
ECOCYC:EG10439
Locus tag
b0460
See related
ASAP:ABE-0001594
Gene type
protein coding
RefSeq status
REVIEWED
Organism
Escherichia coli str. K-12 substr. MG1655 (strain: K-12, substrain: MG1655)
Lineage
Bacteria; Pseudomonadati; Pseudomonadota; Gammaproteobacteria; Enterobacterales; Enterobacteriaceae; Escherichia
Also known as
ECK0454
Summary
Hha and Cnu are paralogs. [More information is available at EcoGene: EG10439]. Hha affects production of multiple proteins, causing pleiotropic effects on catabolite repression and other systems, and these effects are increased under conditions of higher osmotic strength . [More information is available at EcoCyc: EG10439].
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Sequence:
NC_000913.3 (480090..480308, complement)

NC_000913.3Genomic Context describing neighboring genes Neighboring gene putative inner membrane protein Neighboring gene maltose O-acetyltransferase Neighboring gene Hha toxicity modulator TomB Neighboring gene multidrug efflux pump RND permease AcrB

Genomic Sequence:
NC_000913.3

Go to nucleotide: Graphics FASTA GenBank

Related articles in PubMed

  1. Temperature- and H-NS-dependent regulation of a plasmid-encoded virulence operon expressing Escherichia coli hemolysin. Madrid C, et al. J Bacteriol, 2002 Sep. PMID 12193622, Free PMC Article
  2. The Hha protein from Escherichia coli is highly homologous to the YmoA protein from Yersinia enterocolitica. de la Cruz F, et al. Mol Microbiol, 1992 Nov. PMID 1484495
  3. Overproduction of a Clostridium cellulolyticum endoglucanase by mutant strains of Escherichia coli. Blanco A, et al. FEMS Microbiol Lett, 1991 Jun 15. PMID 1884997
  4. Chromosomal mutations that increase the production of a plasmid-encoded haemolysin in Escherichia coli. Godessart N, et al. J Gen Microbiol, 1988 Oct. PMID 2855523
  5. hlyM, a transcriptional silencer downstream of the promoter in the hly operon of Escherichia coli. Jubete Y, et al. J Bacteriol, 1995 Jan. PMID 7798139, Free PMC Article

See all (46) citations in PubMed

GeneRIFs: Gene References Into Functions

What's a GeneRIF?
  1. Hha and StpA greatly enhance H-NS-stimulated pausing by RNAP at 20 degrees C. StpA:H-NS or StpA-only filaments also stimulate pausing at 37 degrees C, a temperature at which Hha:H-NS or H-NS-only filaments have much less effect. In addition, both Hha and StpA greatly stimulate DNA-DNA bridging by H-NS filaments.
    Title: StpA and Hha stimulate pausing by RNA polymerase by promoting DNA-DNA bridging of H-NS filaments.
  2. TomB antitoxin activity is oxygen-dependent and its Yersinia orthologue, YmoB can replace TomB as the Hha antitoxin.
    Title: An oxygen-sensitive toxin-antitoxin system.
  3. The results demonstrated that the chromosomal binding of Hha requires H-NS/StpA, and is necessary for the repression of a subset of genes in the H-NS/StpA regulon.
    Title: Functions of the Hha and YdgT proteins in transcriptional silencing by the nucleoid proteins, H-NS and StpA, in Escherichia coli.
  4. In conclusion, Hha regulates biofilm formation in enterohemorrhagic Escherichia coli O157:H7 by differential regulation of FlhDC and CsgD, the global regulators of motility and curli production, respectively.
    Title: Hha controls Escherichia coli O157:H7 biofilm formation by differential regulation of global transcriptional regulators FlhDC and CsgD.
  5. Authors provide evidence that, as has been shown for H-NS, Hha-like proteins play an essential role facilitating acquisition of horizontally transferred DNA in both Escherichia coli and Salmonella.
    Title: The Hha protein facilitates incorporation of horizontally acquired DNA in enteric bacteria.
  6. Hha has to undergo a conformational change to bind H-NS.
    Title: Essential residues in the H-NS binding site of Hha, a co-regulator of horizontally acquired genes in Enterobacteria.
  7. The authors show that Hha induces excision of prophages, CP4-57 and DLP12, by inducing excision genes and by reducing SsrA synthesis.
    Title: Control and benefits of CP4-57 prophage excision in Escherichia coli biofilms.
  8. A single mutation of cysteine 18 to isoleucine (C18I) in Hha abolishes the repression of the hemolysin operon observed in the wild-type protein.
    Title: A single residue mutation in Hha preserving structure and binding to H-NS results in loss of H-NS mediated gene repression properties.
  9. role of the nucleoid associated proteins H-NS and Hha in the repression of htrA expression at low osmolarity.
    Title: Osmoregulation of the HtrA (DegP) protease of Escherichia coli: an Hha-H-NS complex represses HtrA expression at low osmolarity.
Submit: New GeneRIF Correction

Gene Ontology Provided by EcoCyc

Function Evidence Code Pubs
enables DNA binding IDA
Inferred from Direct Assay
more info
 PubMed 
enables protein binding IPI
Inferred from Physical Interaction
more info
 PubMed 
Process Evidence Code Pubs
involved_in regulation of DNA-templated transcription NAS
Non-traceable Author Statement
more info
 PubMed 
acts_upstream_of_or_within regulation of gene expression IMP
Inferred from Mutant Phenotype
more info
 PubMed 
Component Evidence Code Pubs
located_in cytosol IDA
Inferred from Direct Assay
more info
 PubMed 
Preferred Names
hemolysin expression-modulating protein Hha

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Genome Annotation

The following sections contain reference sequences that belong to a specific genome build. Explain

Reference assembly

Genomic

  1. NC_000913.3 Reference assembly

    Range
    480090..480308 complement
    Download
    GenBank, FASTA, Sequence Viewer (Graphics)

mRNA and Protein(s)

  1. NP_414993.1 hemolysin expression-modulating protein Hha

    See identical proteins and their annotated locations for NP_414993.1

    Status: REVIEWED

    UniProtKB/TrEMBL
    A0A8S7HWV4
    Conserved Domains (1) summary
    PRK10945
    Location:1 → 72
    PRK10945; hemolysin expression modulator Hha
Nucleotide Protein
Heading Accession and Version

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