Fam161A is lost at the core region in wild-type and poc1Δ cells, and BB defects in poc1Δ at high force are associated with loss of Poc16. (A) SIM images of wild-type BBs in longitudinal view stained for Fam161A (c-terminal mCherry, grayscale and green) and Poc1 (magenta). Scale bar is 200 nm. Note that the transition zone population has been saturated after image acquisition to enable visualization of the other Fam161A populations. Fam161A localizes in the core/inner scaffold position, but also sometimes around the BB. (B) Side view of a ciliary row from wild-type (left) and poc1Δ (right) cells expressing Fam161A:mCherry at 30 and 38°C. The cell exterior is at the top of the images. Cells were costained with anti-mCherry and anti-centrin antibodies. Fam161A has two longitudinal localizations, core (white arrowhead) and presumed transition zone (yellow arrowhead), with the latter population being the most consistent in each BB in low-force conditions. Upon shift to 38°C, Fam161A is lost preferentially from the core region in both wild-type and poc1Δ cells. Scale bar is 1 μm. (C) U-ExM-SIM images of wild-type and poc1Δ cells at 30 and 38°C expressing Poc16:GFP. Representative longitudinal and cross-sectional images are shown for wild-type at both temperatures and poc1Δ at 30°C. For poc1Δ at 38°C a montage of four longitudinal views (bottom left) and five cross-sectional views (bottom right) are shown. Figure accompanies Fig. 6 F. Scale bars are 500 nm.