FoxF1 is Required for Ciliogenesis and Distribution of Sonic Hedgehog Signaling Components in Cilium

Background: In vertebrates, cilium is crucial for Hedgehog signaling transduction. Forkhead box transcriptional factor FoxF1 is reported to be associated with Sonic Hedgehog (Shh) signaling in many cases. However, the role of FoxF1 in cilium remains unknown. Here, we showed an essential role of FoxF1 in the regulation of ciliogenesis and in the distribution of Shh signaling components in cilium. Methods: NIH/3T3 cells were serum starved for 24h to induce cilium. Meanwhile, shRNA was used to knockdown the FoxF1 expression in the cells and CRISPR/Cas9 was used to generate the FoxF1 zebrafish mutant. The mRNA and protein expression of indicated genes were detected by the qRT-PCR and western blot, respectively. Immunofluorescence staining was performed to detect the cilium and Shh components distribution. Results: FoxF1 knockdown decreased the cilium length in NIH/3T3 cells. Meanwhile, the disruption of FoxF1 function inhibited the expression of cilium-related genes and caused an abnormal distribution of Shh components in the cilium. Furthermore, homozygous FoxF1 mutants exhibited defective development of pronephric cilium in early zebrafish embryos. Conclusion: Together, our data illustrated that FoxF1 is required for ciliogenesis in vitro and in vivo and for the proper localization of Shh signaling components in cilium.