Cep135/Bld10 is a conserved centriolar protein required for the formation of the 
central cartwheel, an early intermediate in centriole assembly. Surprisingly, 
Cep135/Bld10 is not essential for centriole duplication in Drosophila, 
suggesting either that Cep135/Bld10 is not essential for cartwheel formation, or 
that the cartwheel is not essential for centriole assembly in flies. Using 
electron tomography and super-resolution microscopy we show that centrioles can 
form a cartwheel in the absence of Cep135/Bld10, but centriole width is 
increased and the cartwheel appears to disassemble over time. Using 3D 
structured illumination microscopy we show that Cep135/Bld10 is localized to a 
region between inner (SAS-6, Ana2) and outer (Asl, DSpd-2 and D-PLP) centriolar 
components, and the localization of all these component is subtly perturbed in 
the absence of Cep135/Bld10, although the ninefold symmetry of the centriole is 
maintained. Thus, in flies, Cep135/Bld10 is not essential for cartwheel assembly 
or for establishing the ninefold symmetry of centrioles; rather, it appears to 
stabilize the connection between inner and outer centriole components.