Targeted gene disruption by homologous recombination in the oral spirochete Treponema denticola ATCC 35405

Abstract

Periodontal Disease • Periodontal disease is a bacterial infection of the gums and supporting structures in the mouth, including ligament and alveolar bone, which is triggered by the build-up of microorganisms that create a biofilm known as plaque (Bascones-Martinez and Figuero-Rutz, 2004; Liebana et al., 2004). Treponema denticola • Treponema denticola is a Gram-negative, anaerobic, motile and helical rod which belongs to a group of bacteria known as the “red complex” that is frequently associated with periodontitis (Edwards et al., 2003; Kuramitsu, 2003). • Numerical prevalence, high association level and spatial location within infected sites suggest T. denticola plays a key role in disease progression via a number of virulence factors (Fenno and McBride, 1998). Purpose • The purpose of this investigation was to disrupt two potentially virulent genes in T. denticola: TDE1343 and TDE 1658, using a gene transfer system developed by Li and Kuramitsu (1996). • TDE1343 is a homolog of the htrA/degP gene in E. coli which codes for a heat-shock protein. The HtrA/DegP protein combines the activities of the chaperones and the proteases to control the degradation of misfolded proteins (Strauch and Beckwith, 1988). • TDE1658 is a homolog of the surA gene in E. coli which codes for a periplasmic peptidyl-prolyl isomerase. SurA was found to be involved in the correct folding and maturation of outer membrane proteins thus enabling the cell to communicate with the external environment (Behrens et al., 2001).