Figure 1. Ciliogenesis.

The production of multiciliated cells from precursors occurs through an orderly process known as ciliogenesis, which begins with a single precursor of an organelle called the basal body, located inside another organelle, the centrosome. As the cell differentiates, the basal-body precursor multiplies and matures. Basal bodies then migrate and dock to the surface of the cell, extending microtubular structures into the extracellular environment to form cilia. Song et al.² report that, as precursors undergo differentiation, six miRNA molecules expressed by three related genetic regions regulate normal ciliogenesis in mice and frogs. The miRNAs inhibit translation of the messenger RNA that encodes the centrosomal protein CP110. The authors find that enhanced expression of CP110, brought about by simultaneous deletion of the six miRNAs, prevents normal docking of basal bodies to the cell surface (not shown).