Templates for mRNA in situ hybridization probes were cloned by PCR or SMARTer 3’/5’-RACE (Clontech) from cDNA or genomic DNA, or synthesized de novo (Twist Bioscience). See Supporting Information for detailed sequences and sequence IDs to search for further information in the ANISEED database (Dardaillon et al., 2020 (link)). In vitro transcription of labeled probes for fluorescent in situ hybridization was performed as previously described (Ikuta & Saiga, 2007 (link); Stolfi, Lowe, et al., 2014 ). To detect cilia, larvae were incubated with anti-acetylated α-tubulin primary antibody (clone 6-11B-1, Sigma) and AlexaFluor-488 secondary antibody (ThermoFisher) as previously described (Pennati et al., 2015 (link)). Cell outlines were counterstained with phalloidin AlexFluor-546 conjugate (ThermoFisher) incubated 1:50 for at least 2 hours prior to final washes, and nuclei were labeled with DAPI during the final wash. Embryos were imaged on upright and inverted epifluorescence microscopes (Leica), or TCS SP5 AOBS and TCS SP8 X scanning point confocal systems (Leica).