Have a personal or library account? Click to login
A Mini-Review of Enteroaggregative Escherichia coli with a Specific Target on the Virulence Factors Controlled by the AggR Master Regulator Cover

A Mini-Review of Enteroaggregative Escherichia coli with a Specific Target on the Virulence Factors Controlled by the AggR Master Regulator

Polish Journal of Microbiology
Volume 72 (2023): Issue 4 (December 2023)
By: Jeannett Alejandra Izquierdo-Vega,  Rubi Joseline Castillo-Juarez,  Manuel Sánchez-Gutiérrez,  Miguel A. Ares and  Miguel A. De La Cruz  
Open Access
|Dec 2023

Figures & Tables

Fig. 1.

Schematic representation of EAEC virulence factors. Most EAEC virulence factors are regulated by the AggR transcriptional activator encoded on the plasmid of aggregative adherence (pAA). EAEC strains adhere in a “brick stacking” pattern and spread in intestinal epithelial cells via aggregative adherence fimbria (AAF). This AAF presents at least five antigenic variants regulated by the AggR master regulator. The AggR transcription factor also activates the genes that encode the anti-aggregation protein (Aap, dispersin) and its anti-aggregation transporter (Aat), and the type VI secretion system (T6SS). EAEC strains can form robust biofilms, which promote high resistance to desiccation, starvation, and host immune response. EAEC secretes at least three toxins: E. coli heat-stable enterotoxin (EAST-1), plasmid-encoded toxin, (Pet), and protein involved in colonization (Pic, with mucinase activity), which are not controlled by the AggR regulator, causing an increase in chloride secretion that correlates with secretory diarrhea.
Schematic representation of EAEC virulence factors. Most EAEC virulence factors are regulated by the AggR transcriptional activator encoded on the plasmid of aggregative adherence (pAA). EAEC strains adhere in a “brick stacking” pattern and spread in intestinal epithelial cells via aggregative adherence fimbria (AAF). This AAF presents at least five antigenic variants regulated by the AggR master regulator. The AggR transcription factor also activates the genes that encode the anti-aggregation protein (Aap, dispersin) and its anti-aggregation transporter (Aat), and the type VI secretion system (T6SS). EAEC strains can form robust biofilms, which promote high resistance to desiccation, starvation, and host immune response. EAEC secretes at least three toxins: E. coli heat-stable enterotoxin (EAST-1), plasmid-encoded toxin, (Pet), and protein involved in colonization (Pic, with mucinase activity), which are not controlled by the AggR regulator, causing an increase in chloride secretion that correlates with secretory diarrhea.

Fig. 2.

Regulatory model of AggR and Aar on the EAEC virulence genes. AggR master regulator activates the virulence regulon that includes: Aar regulatory protein, aggregative adherence fimbriae II (AAF/II), Type VI secretion system (T6SS), anti-aggregation protein (Aap, dispersin), and anti-aggregation transporter (Aat). Aar directly binds AggR, blocking its transcription activity. In addition, Aar forms multiprotein complexes together with H-NS, altering the repressor function of nucleoid protein on its promoter.
Regulatory model of AggR and Aar on the EAEC virulence genes. AggR master regulator activates the virulence regulon that includes: Aar regulatory protein, aggregative adherence fimbriae II (AAF/II), Type VI secretion system (T6SS), anti-aggregation protein (Aap, dispersin), and anti-aggregation transporter (Aat). Aar directly binds AggR, blocking its transcription activity. In addition, Aar forms multiprotein complexes together with H-NS, altering the repressor function of nucleoid protein on its promoter.

Virulence genes regulated by AggR*_

LocationVirulence factorRegulated genesDescription
pAA2 plasmidAAF/IIaafA, aafB, aafC, aafDmajor subunit, minor subunit, usher protein, chaperone of AAF/II
dispersinaapdispersin (antiaggregation protein)
dispersin export apparatusaatA, aatB, aatC, aatD, aatPTolC-like outer membrane protein, hypothetic protein, ABC transporter, N-acyltransferase, permease protein
AggRaggRAraC/XylS-type transcriptional regulator
AaraarANR-family regulator
ORF3EC042_RS26240 (pAA003)isoprenyl diphosphate synthase
Idi (ORF4)idiisopentenyl-diphosphate delta-isomerase
Shfshfpolysaccharide deacetylase
EC042_RS30880 (pAA005A), EC042_RS26330 (pAA0020), (pAA0047), (pAA0056)hypothetical proteins
ChromosomeType VI secretion systemaaiA-U (EC042_RS24360–EC042_RS24465)T6SS putative proteins
EC042_RS16995 (EC042_3181)putative transcriptional regulator
EC042_RS17000 (EC042_3182)ParB-type nuclease
EC042_RS17030 (EC042_3187)putative helicase
EC042_RS17005, EC042_RS17010, EC042_RS21290 (EC042_3183, EC042_3184, EC042_4006)hypothetic proteins
DOI: https://doi.org/10.33073/pjm-2023-037 | Journal eISSN: 2544-4646 | Journal ISSN: 1733-1331
Journal RSS Feed
Language: English
Page range: 347 - 354
Submitted on: Jun 23, 2023
Accepted on: Sep 8, 2023
Published on: Dec 16, 2023
Published by: Polish Society of Microbiologists
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year
Keywords:
aggregative adhesion fimbriae,
AggR regulator,
aggregative adhesion plasmid,
dispersin,
enteroaggregative
Related subjects:
Life sciences,
Microbiology and virology

© 2023 Jeannett Alejandra Izquierdo-Vega, Rubi Joseline Castillo-Juarez, Manuel Sánchez-Gutiérrez, Miguel A. Ares, Miguel A. De La Cruz, published by Polish Society of Microbiologists
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Volume 72 (2023): Issue 4 (December 2023)Next article