Fig. 6. Ciliary defects in Rfx mutants. (A) An antennal scolopidium of the Johnston's organ in longitudinal and cross-sections. tb, tubular bundle; cd, ciliary dilation; af, axial filament; dc, dendritic cap; sr, scolopale rods; ci, cilium. (B-J) Transmission electron micrographs of scolopidia of the Johnston's organ of wild-type and Rfx mutant adults. Cross-sections of wild-type (B,D,F) and Rfx²⁵³/Rfx⁴⁹ scolopidia (C,E,G,H). Longitudinal sections of wild-type (I) or Rfx²⁵³/Rfx⁴⁹ scolopidia (J). In B,C, scolopidia (sc, arrows) are sectioned at different levels from distal (up) to proximal (down). (B) Cilia are observed on proximal sections in wild-type antenna. (C) Scolopidia are less well organized and no typical cilia are observed in the Rfx mutant antenna, the arrowhead indicates a noticeably disorganized scolopidium. (D) Enlargement of a typical proximal section of a wild-type scolopidium presents the nine microtubule doublets (ci, arrowhead). (E) Enlargement of a proximal section of a Rfx mutant scolopidium shows that no microtubule doublet is present (arrowhead). (F-H) Enlargement of distal scolopidia sections. No differences are observed between wild-type (F) and Rfx⁴⁹/Rfx²⁵³ mutant (G,H) dendritic cap structures. (I,J) Longitudinal sections through scolopidia. (I) The axial filament clearly appears in the control dendrite process. (J) No typical axial filament is observed at the expected position (arrowheads) in longitudinal section of three Rfx mutant scolopidia.