Targeting septins by RNAi disrupts F actin structures on the inclusion, while inhibiting F actin disrupts septin cages. (A and B) HeLa cells were transfected with siRNA targeting SEPT9 (A), or SEPT2-specific shRNA was induced (B). At 24 h posttransfection/-induction, cells were infected with C. trachomatis, and they were fixed at 30 h postinfection and stained with phalloidin-Alexa 546 to detect F actin and with Hoechst dye. Inclusions are indicated by arrows. Cell nuclei are marked with asterisks. (C) HeLa cells were infected for 30 h and stained for SEPT2 or SEPT9 and F actin as indicated. To some aliquots, cytochalasin D was added 30 min prior to fixation. DNA was stained with Hoechst dye. Inclusions are indicated by arrows. Cell nuclei are marked with asterisks. Scale bar, 10 µm. All images are representative of 3 independent experiments.
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