Figure 4

Cilia length inversely correlates with centriolar Fbxo41 levels and requires a functional F-box domain. (a–c) Primary hippocampal neurons were infected with the indicated constructs at DIV1, fixed at DIV15, and immunostained with GFP (green), ACIII (red) and MAP2 (blue) antibodies. Fbxo41^WT, but not Fbxo41^ΔCΔF mutant levels at centrosome correlate with cilia length: (a) neuron with low Fbxo41^WT expression (green) and long cilia (red), (b) neuron with high Fbxo41^WT expression and small/no cilia, and (c) neuron with high expression of Fbxo41^ΔCΔF mutant and a long cilium. The bottom panel is a pseudo color image of EGFP-Fbxo41 to emphasize the difference in Fbxo41 expression. Calibration bar illustrates color-coded signal intensity. Scale bars, 2 μm. (d) Cilia length inversely correlates with centriolar Fbxo41 levels. Scatterplot displays the relationship between Fbxo41^WT intensity at the centrioles and cilia length. Each dot represents a single measurement from an individual neuron (n = 55 cells). The black line shows a linear fit through the data. Inset displays the Spearman correlation coefficient (rs) and significance (p-value). (e) Cilia length does not correlate with centriolar Fbxo41^ΔCΔF levels. Scatterplot displays the lack of relationship between Fbxo41^ΔCΔF intensity at the centrioles and cilia length. Each dot represents a single measurement from an individual neuron (n = 73 cells). The black line shows a linear fit through the data. Inset displays the Spearman correlation coefficient (r_s) and significance (p-value). (f) Similar mean centriolar intensity between neurons infected with Fbxo41^WT or Fbxo41 ^ΔCΔF. Data from (d,e). Mann-Whitney Test, p = 0.155. (g) Cilia length was reduced by Fbxo41^WT, but not by Fbxo41 with a deleted or mutated F-box domain. Kruskal-Wallis Test, *** p < 0.001. Data was pooled from two independent experiments. Data are represented as mean ± SEM.