Role of the Hha/YmoA family of proteins in the thermoregulation of the expression of virulence factors.

Virulent bacteria are able to sense temperature changes and respond by modifying the expression of--among others--genes that code for virulence factors. The chromatin-associated protein H-NS has been shown to play a role in the thermomodulation of virulence factor expression. In addition to H-NS, proteins of the Hha/YmoA family have also been identified in different enterobacteria as participating in the thermoregulation of some virulence factors. For one of these proteins, the Hha protein, it has been shown that it interacts with H-NS, and both proteins form a nucleoid-protein complex responsible for the thermoregulation of, at least, E. coli hemolysin. The presence of genes coding for homologues of both proteins on some conjugative plasmids and their relation to thermoregulation suggests that this complex could also play a role in the regulation of plasmid transfer.