Fig. 1. CARP3 is a flagellar tip regulator of social motility (SoMo) and is essential for colonization of tsetse fly salivary glands.

a SoMo assays of procyclic T. brucei AnTat 1.1 wild type (WT), carp3 knock-out (KO, independent clones KO1, KO2) or in situ CARP3 rescue (resc, independent clones resc1, resc2). The Western blot was probed with anti-CARP3 and anti-PFR-A/C (loading control). b SoMo assay upon tetracycline (Tet)-inducible RNAi of CARP3 (-Tet / +Tet 24 h) and the parental AnTat 1.1 1313 cell line. The Western blot shows CARP3 repression detected by antibodies as in (a). c Illustration of the digestive system and the salivary glands of a tsetse fly (adapted from⁹¹). d Infection rates of tsetse fly midgut (MG) or salivary glands (SG) with T. brucei AnTat 1.1 cell lines as in (a). Flies were dissected 34-36 days p.i., n (flies) = 48 (WT), 50 (KO1), 50 (KO2), 40 (resc1). 10 mM L-glutathione was included in the blood meal (Institute of Tropical Medicine Antwerp tsetse fly colony). Indirect immunofluorescence analysis of CARP3 (green) in T. brucei AnTat 1.1 procyclic form WT (e) or carp3 KO (f). The upper panels show CARP3 (green) and the nuclear and mitochondrial DNA stained with DAPI (blue), the lower panels show an overlay with the axoneme (red; stained with the antibody mAB25). In (e) cells in different cell cycle stages are shown (1K1N, 2K1N, 2K2N; K kinetoplast, N nucleus). g Indirect immunofluorescence analysis of CARP3 (green) as in (e, f) during culture differentiation from bloodstream to procyclic forms. Scale bar in (e–g) 5 µm. Source data to (a, b) and (d) are provided as Source Data file.