LEE-encoded regulator (Ler)

Ler (LEE-encoded regulator) is a DNA-binding protein that functions as the master regulator of virulence gene expression in enterohemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC). It activates transcription of multiple operons within the locus of enterocyte effacement (LEE) pathogenicity island, which encode components for a type III secretion system and other virulence factors. Ler counteracts H-NS-mediated repression by binding directly to regulatory promoter regions of target genes, disrupting H-NS-dependent repressor complexes and allowing transcriptional activation. Its regulation is essential for successful colonization during infection.

Disrupts H-NS-mediated repression of virulence genes