FIG 4 .

Genetic disruption of cholesterol homeostasis inhibits the intracellular growth of C. burnetii. (A) Images of NPC-1 shRNA-mediated inhibition of intracellular C. burnetii. Panels I and IV show Nomarski images of control (empty-vector shRNA) THP-1 cells and cells transfected with NPC-1 shRNA. Panels II and V show fluorescence signals generated from the shRNA vector. Panels III and VI show intracellular C. burnetii. For direct comparison of fluorescence signals, images were taken at a constant exposure. Scale bars, 100 µm. (B) Growth curve of C. burnetii in THP-1 cells transfected with the control and three different constructs of NPC-1 shRNA. Western blot of NPC-1 levels relative to those in an actin control in cells transfected with NPC-1 shRNA constructs and control shRNA.