Fig. 1: The consensus average of nine doublets in mouse sperm possesses unique features in non-motor protein complexes including MIPs, N-DRCs and RSs.

a, Schematic of a cross-section view of the conserved (9 + 2) configuration of axonemes in motile cilia. One doublet is highlighted, and its associated motor and non-motor protein complexes are labeled. The dyneins, N-DRCs, MIPs and RSs are colored in pink, green, orange and cyan, respectively. b–d, Three views of the consensus subvolume average of nine doublets in mouse sperm axonemes. Different protein complexes are highlighted as described in a. c, The clefts in the top of RS1 and RS2 and the ‘S’-shaped head of RS3 are indicated by the red arrowheads and dashed line, respectively. e, Schematic of the doublet microtubule with individual protofilaments labeled. Two cross-sections of the A tubule and one longitudinal view of the isolated MIP densities are shown. The MIPs are colored in orange. The protofilaments connecting to the MIPs and the periodicities for the connections are indicated. f,g, Comparison of densities of N-DRCs and RSs from mouse sperm flagella (this study) and human respiratory cilia (EMD-5950)³¹. f, Additional densities in the mouse sperm N-DRCs are highlighted (light red). g, The unique densities of a barrel and an RS2–RS3 cross-linker in the mouse sperm axoneme are highlighted in blue and red, respectively.