TABLE 3:

Summary of structural defects in pacrg and pacrg; fap20 mutants.

	Strains
	WT	pacrg	pacrg; fap20
IJ	IJ is formed by alternating PACRG and FAP20 subunits with a periodicity of 8 nm	FAP20 assembles into the IJ, but loss of PACRG leaves hole between the FAP20 subunit every 8 nm.	Loss of the entire IJ density and the B-tubule protofilament B10 is detached from the A-tubule.
IDA b	IDA b is absent from ∼40% of axonemal repeats and shows asymmetric distribution both among DMTs and from proximal to distal (i.e., absent proximal, but present distal, except for selected DMTs (1, 5, 9). WT structures also reported by Bui et al. (2012); Lin et al. (2012).	IDA b is absent in ∼74% of ­axonemal particles.	IDA b is absent in ∼94% of ­axonemal particles.
B-tubule beak-MIP	Three ribbons attaching to protofilaments B3–5; present in ∼32% of axonemal repeats with asymmetric distribution both among DMTs (preferred DMTs 1, 5, 6) and from proximal to distal (distal less). WT structures also reported by Hoops and Witman (1983); Nicastro et al. (2011); Bui et al. (2012).	Beak-MIP is reduced in size (mostly only at B5) and number (present in ∼20% of axonemal particles).	Beak-MIP is reduced in size (mostly only at B5) and number (present in ∼7% of axonemal particles).
I1 tether base	I1 tether base forms a microtubule ­attachment of the tether/tether head complex. WT structures also reported by Fu et al. (2018).	I1 tether base is reduced in size.	I1 tether base is completely missing in the averaged ­axonemal repeats.