1700012B09Rik, a FOXJ1 effector gene active in ciliated tissues of the mouse but not essential for motile ciliogenesis

- 1700012B09Rik is a novel FOXJ1 target conserved within amniotes.
- It is expressed in all motile and a few non-motile ciliated tissues of the mouse.
- 1700012B09RIK-GFP stably expressed in IMCD3 cells localises to basal bodies of cilia.
- TAP analysis suggests association with the BBSome protein complex.
- 1700012B09Rik KO mice apparently form normal, functional motile and non-motile cilia.

In humans and mice, motile cilia occur on the surface of the embryonic ventral node, on respiratory and ependymal epithelia and in reproductive organs where they ensure normal left-right asymmetry of the organism, mucociliary clearance of airways, homeostasis of the cerebrospinal fluid and fertility. The genetic programme for the formation of motile cilia, thus critical for normal development and health, is switched on by the key transcription factor FOXJ1. In previous microarray screens for murine FOXJ1 effectors, we identified candidates for novel factors involved in motile ciliogenesis, including both genes that are well conserved throughout metazoa and beyond, like FOXJ1 itself, and genes without overt homologues outside higher vertebrates.Here we examine one of the novel murine FOXJ1 effectors, the uncharacterised 1700012B09Rik whose homologues appear to be restricted to higher vertebrates. In mouse embryos and adults, 1700012B09Rik is predominantly expressed in motile ciliated tissues in a FOXJ1-dependent manner. 1700012B09RIK protein localises to basal bodies of cilia in cultured cells. Detailed analysis of 1700012B09RiklacZ knock-out mice reveals no impaired function of motile cilia or non-motile cilia. In conclusion, this novel FOXJ1 effector is associated mainly with motile cilia but - in contrast to other known FOXJ1 targets - its putative ciliary function is not essential for development or health in the mouse, consistent with a late emergence during evolution of motile ciliogenesis.