H-NS and genomic bridge building: lessons from the human pathogen Salmonella Typhi

The H-NS protein has emerged as one of the leading causes of transcriptional repression in Gram-negative bacteria. In a paper published in this issue, De la Cruz and colleagues shed new light on the role of DNA curvature in the repressive mechanism, using a porin gene promoter from the human pathogen Salmonella Typhi as their experimental system (De la Cruz et al., 2009). Their data help to deepen our understanding of the importance of local DNA structure in facilitating the interaction of H-NS with its target sites in DNA and in establishing an effective nucleoprotein complex for the repression of transcription.