RNAseq analysis of Xenopus laevis wildtype and emi2 mutant multiciliated cells during and post differentiation

Multiciliated cells (MCCs) form when progenitors massively expand centriole number, yielding the hundreds of basal bodies required to extend multiple motile cilia. This organelle biogenesis is promoted transcriptionally by Multicilin acting in a complex with the E2F transcription factors, which activates the expression of genes known to be involved required to form centrioles during the cell cycle, but also requires a cell cycle state required for the centrosome cycle. Multicilin also activates the expression of Emi2 (fbxo43) an inhibitor of the APC/C ubiquitin ligase. In Emi2 mutants, basal body formation during MCCl differentiation is blocked. RNAseq analysis is used to show that gene expression associated with MCC differentiation is upregulated normally in Emi2 mutants, but surprisingly is not downregulated when MCC differentiation is complete. Emi2 is required to promote the centrosomal cycle during MCC differentiation, but then also acts to turn off gene expression associated with centriole biogenesis in differentiated cells. Overall design: An inducible form of multicilin was used to promote MCC differentiation in Xenopus skin progenitors from both wildtype and emi2 mutant embryos, and analyzed by RNAseq at both stage 17 (mid-differentiation) and stage 26 (when differentiation is complete)