Difference between revisions of "Part:BBa K4583012"

Revision as of 12:49, 5 October 2023

PesaS

PesaS

Usage and Biology

QS system

Quorum sensing (QS) is a natural form of cell-cell communication that regulates the metabolic behaviour of bacteria based on changes in their local cell density. As cell density increases, signalling molecules accumulate and are sensed by QS-controlled gene expression regulators, which turn on relevant gene expression.

Esa I/R system

The Esa I/R system is quite special from traditional QS system. The EsaI/R QS system is homologous to the LuxI/R QS system and originates the maize pathogen--Pantoea stewartii subsp. stewartia. EsaR can act as both transcriptional activator and repressor. PesaR is a natural EsaR-repressed promoter, whereas PesaS is a natural EsaR-activated promoter. At low cell density (low ρ), EsaR binds to its esa box to turn off PesaR and turn on PesaS. In the presence of AHL, EsaR can bind to AHL and release from the DNA. Thus, at high cell density(high ρ), the PesaR is turned on and the PesaS is turned off[2].

PesaS

PesaS is a natural EsaR-activated promoter."At low cell density, EsaR binds to its target DNA sequence (esa box) to turn off expression of downstream genes of the PesaR promoter and turn on expression of downstream genes of the PesaS. In the presence of AHL, EsaR releases the esa box. Thus, at high cell density, the PesaR is turned on and the PesaS is turned off."

Sequence and Features