The potential importance of these shifts in Y. pestis lipid A as an immune evasion tactic is supported by the attenuation of strains with forced expression of a hexa-acylated structure due to heterologous expression of E. coli lpxL lauryl acyltransferase enzyme after infection in WT, but not TLR4-deficient, mice [14]. The gene discussed is TLR4; the disease is infection.