sulA-independent division inhibition in his-constitutive strains of Salmonella typhimurium.

Constitutive expression of the S. typhimurium histidine operon causes multiple phenotypic changes including strong filamentation. However, the SOS regulatory network is not involved in the inhibition of cell division. The possibility of SOS-independent activation of sulA gene transcription has been ruled out using sulA-lacZ fusions. These results suggest the existence of a pathway of division inhibition unrelated to sulA and not regulated by the SOS system.