Part:BBa_K2688020

Ler is a nucleoid associated protein encoded by LEE type III secretion system present in some pathogenic E. coli. H-NS and Ler belong to the same family of protein of proteins qualified as ‘silencers’ of foreign DNA expression, the « H-NS family ». However, it has been reported that Ler can counteract the H-NS silencing on the LEE island.

Our results show that Ler1 can be used to generate heterogeneity of LEE5 promoter (see BBa_K2688016 and BBa_K2688018) activity within E. coli population. Under some conditions (e.g. 50 ng/ml anhydrotetracyclin), a bimodal expression of LEE5 can be observed in E. coli harbouring pSB1C3-tetO-RBS-ler1 and an integrated copy of LEE5-gfp.