Disease relevance of espA

• Norepinephrine was effective in promoting cecal adherence of a non-O157 E. coli strain as well as E. coli O157:H7 eae or espA mutant strains that are incapable of intimate mucosal attachment [1].

High impact information on espA

• To investigate the role of Esp proteins in disease, mutations in espA and espB were constructed in rabbit EPEC serotype O103 and infection characteristics were compared to that of the wild-type strain using histology, scanning and transmission electron microscopy, and confocal laser scanning microscopy in a weaned rabbit infection model [2].
• Each espA, -B, -D mutant could be fully complemented in trans by the corresponding cloned esp genes from both the parental strain and the CPE-negative E2348/69 strain, indicating that no single esp encodes the information needed to confer the CPE phenotype [3].
• Consistently, a deletion of the espA gene completely abolished the capacity of such STEC mutants to bind to HeLa cells and to induce actin rearrangements [4].
• It is concluded that espA encodes an EPEC secreted protein that is necessary for activating epithelial signal transduction, intimate contact, and formation of attaching and effacing lesions, processes which are central to pathogenesis [5].
• A mutant with a non-polar insertion in espA does not secrete this protein, activate epithelial cell signal transduction or cause cytoskeletal rearrangement [5].

Biological context of espA

• These phenotypes were complemented by a cloned espA gene [5].
• DNA-sequence analysis of a region between eaeA and eaeB identified a predicted open reading frame (espA) that matched the amino-terminal sequence of a 25 kDa EPEC secreted protein [5].
• Complementation with plasmids containing EPEC espA or/and espB genes into RDEC-1 mutant strains demonstrated that they were functionally interchangeable, although the EPEC proteins mediated higher levels of invasion [6].
• There was no DNA sequence diversity in the sequenced portions of the seven housekeeping genes and espA [7].
• The esp operon is controlled by a promoter located 94 bp upstream from the ATG start codon of the espA gene [8].

Anatomical context of espA

• In addition, we detected morphologically and antigenically similar EspA filaments in all but one of the bacterial strains examined including recombinant, non-pathogenic E. coli expressing espA from a cloned locus for enterocyte effacement region (HB101(pCVD462)) [9].
• We have cloned and determined the nucleotide sequences of the espA, espB and espD homologues from an E. coli strain (4221) isolated from a dog which manifested the attaching and effacing lesions in the small intestine [10].
• We have previously shown that in enteropathogenic and enterohemorrhagic Escherichia coli the type III secreted protein EspA is assembled into a filamentous organelle that attaches the bacterium to the plasma membrane of the host cell [11].

Other interactions of espA

• Finally, expression of espA is controlled by a quorum-sensing (QS) regulatory mechanism, and the EPEC qseA QS mutant also forms altered biofilms, suggesting that this signaling mechanism plays an important role in EPEC biofilm development [12].
• Fecal shedding periods of the type III secretion system-related gene (espA and sepL) deletion mutants were clearly shorter than that of the wild-type EHEC O157:H7 strain [13].
• The microarray was also tested for its ability to distinguish among phylogenetic groups of genes by using gene probes derived from the attaching-and-effacing locus (espA, espB, tir) [14].

References