In Vivo Screening of Artificial Small RNAs for Silencing Endogenous Genes in Escherichia coli

Bacterial noncoding small RNAs (sRNAs) modulate expression of numerous genes through antisense interactions with mRNAs. This chapter describes an in vivo screening strategy to engineer artificial sRNAs that can posttranscriptionally regulate desired endogenous genes in Escherichia coli . Artificial sRNA libraries are constructed by randomizing the antisense domain of natural sRNAs and screened for gene silencing activity using a cotransformed reporter vector. These small synthetic riboregulators can be used in synthetic gene circuits to control cell functions by directly targeting endogenous genes.