Fig. 1. Silencing of DLP1 induces elongation of the peroxisomal compartment. COS-7 cells stably expressing GFP-PTS1 were transfected with DLP1 siRNA duplexes (siRNA) and processed for immunofluorescence (A-E) and immunoblotting (G) with anti-DLP1 antibodies 48 hours after the first transfection. (A,B) Control cells (Con) transfected with luciferase siRNA duplexes. (C-E) COS-7 cells transfected with DLP1 siRNA duplexes. The arrow in C points to a peroxisomal aggregate. (E) A high magnification view of elongated peroxisomes. Note the segmented appearance of the organelles (arrowheads). Arrows point to largely elongated, tubular peroxisomes. N, nucleus. (F) Quantification of peroxisome morphology at different time points after transfection with siRNA. The data are from five to seven independent experiments and are expressed as means ± s.d. (P<0.01 when compared to controls). (G) Immunoblots of homogenates prepared from controls treated with buffer (Con) and cells transfected with luciferase (Luc) or DLP1 siRNA duplexes (D1) using anti-DLP1 and anti-tubulin (Tub) antibodies. Homogenates were separated in a supernatant (Sup) and pellet (P) fraction. Equal amounts of protein (DLP1, 70 µg/lane; Tub, 30 µg/lane) were loaded onto the gels. Anti-tubulin was used to check for equal loading and integrity of the cells after transfection. Bars, 10 µm.