A putative curved DNA region upstream of in plays a key role in transcriptional regulation by H-NS.

It is well established that in , the histone-like nucleoid structuring (H-NS) protein also functions as negative regulator of transcription. However, the exact mode of regulation of transcription by H-NS has not been studied extensively. Here, we report the multicopy effect of dominant-negative alleles on the transcription of based on expression of transcriptional fusion in ∆, ∆, ∆ and strains. Our results indicate that H-NS defective in recognizing curved DNA fails to repress transcription significantly, while nonoligomeric H-NS molecules still retain the repressor activity to an appreciable extent. Together with bioinformatics analysis, our study envisages a critical role for the putative curved DNA region present upstream of promoter in the transcriptional regulation of by H-NS.