Notch decides numbers of motile versus nonmotile cilia in the LR Organizer
Foxj1a is necessary and sufficient to specify motile cilia. Using transcriptional studies and slow-scan two-photon live imaging capable of identifying the number of motile and immotile cilia, Bárbara Tavares and collaborators at CEDOC established that the final number of motile cilia depends on Notch signalling (NS). They found that despite all left-right organizer (LRO) cells express foxj1aand the ciliary axonemes of these cells have dynein arms, some cilia remain immotile. They found that this decision is taken early in development in the Kupffer’s Vesicle (KV) precursors the readout being her12 transcription. They further demonstrated that overexpression of either her12 or Notch intracellular domain (NICD) increases the number of immotile cilia at the expense of motile cilia, and leads to an accumulation of immotile cilia at the anterior half of the KV. This disrupts the normal fluid flow intensity and pattern, with consequent impact on left-right (L-R) axis establishment.
See the article entitled “Notch/Her12 signalling modulates, motile/immotile cilia ratio downstream of Foxj1a in zebrafish left-right organizer” published in eLIFE.