摘要：Light-regulated gene expression systems allow controlling gene expression in space and time with high *** to previous synthetic light sensors that incorporate two-component systems which require localization at the plasma membrane,soluble one-component repression systems provide several advantageous ***,they are soluble and able to diffuse across the ***,they are smaller and of lower complexity,enabling less taxing expression and optimization of fewer ***,repression through steric hindrance is a widespread regulation mechanism that does not require specific interaction with host factors,potentially enabling implementation in different ***,we present the design of the synthetic promoter P_(EL)that in combination with the light-regulated dimer EL222 constitutes a onecomponent repression *** by previously engineered synthetic promoters and the Escherichia coli lacZYA promoter,we designed P_(EL)with two EL222 operators positioned to hinder RNA polymerase binding when EL222 is bound.P_(EL)is repressed by EL222 under conditions of white light with a light-regulated repression ratio of ***,alternating conditions of darkness and light in cycles as short as one hour showed that repression is *** design of the P_(EL)EL222 system herein presented could aid the design and implementation of analogous one-component optogenetic repression ***,we compare the P_(EL)-EL222 system with similar systems and suggest general improvements that could optimize and extend the functionality of EL222-based as well as other one-component repression systems.