Functional analysis of PIERCE1, in motile ciliogenesis

Multiciliated cells are important for mucociliary clearance in the airways and ciliopathies, including Primary Ciliary Dyskinesia (PCD) that arise from defects in motile cilia. We interrogated existing data and identified a number of novel candidate genes temporally associated with ciliogenesis. Expression of these genes were analysed in mouse tracheal epithelial cells and nasal epithelial cells during mucociliary differentiation at the air liquid interface (ALI). This report focuses on a poorly characterised gene encoding the protein ‘PIERCE1’. Transcriptional analysis of pierce1 revealed an expression pattern temporally associated with ciliogenesis during differentiation of ALI airway epithelial cells. pierce1 also show enriched expression in motile ciliated mouse tissues. Transient morpholino knock down of pierce1 in early zebrafish showed phenotypes consistent with abnormalities in motile cilia and live imaging showed severe cilia motility defects in kupffer’s vesicle. Finally, we generated maternal zygotic loss-of-function alleles at the zebrafish pierce1 locus using the CRISPR/Cas9. These mutants showed mild laterality defects and live imaging showed partial abnormal cilia motility. Our data validated our bioinformatic approach to identifying novel ciliogenesis genes and suggest that PIERCE1 may play a role in cilia function.