performed histology and supplied reagents. in the endoplasmic reticulum from arachidonic acid, a 20-carbon polyunsaturated fatty acid released from membrane phospholipids1. COX-1 serves a homeostatic function and is responsible for basal, constitutive prostaglandin synthesis, whereas COX-2 increases production of prostaglandins during inflammatory response and in cancer1. The PG precursor is usually metabolized by prostaglandin synthases to form structurally related, bioactive prostanoids in various tissues, including PGE2, PGD2, PGF2 PGI2 and Thromboxane A2 (TxA2)1. PGE2 functions through activation of G-protein-coupled receptors (GPCRs), including EP1 through EP4. Among them, EP2 and Xanomeline oxalate EP4 increase the intracellular cyclic adenosine monophosphate (cAMP) and activate protein kinase A (PKA) signaling1, 3. Although prostaglandins have important functions in a variety of physiological and pathological processes, their functions in ciliogenesis have not been previously investigated and remain virtually unknown. Cilia are formed and extended by IFT, which transports cargo proteins along microtubules from the base to the tip of the cilium and back to the cell body. This process is usually mediated by kinesins in the anterograde direction and by cytoplasmic dynein motor in the retrograde direction4, 5. Basal body proteins are also essential for cilia formation. They anchor the cilium at the cell surface, provide template for microtubules in the ciliary axoneme, and serve as a relay station for protein and lipid traffic from the Golgi complex to the Rabbit Polyclonal to AIFM1 ciliary membrane6, 7. Ciliary dysfunction causes multisystemic genetic disorders commonly known as human ciliopathies5, 8. Many developmental pathways have been shown to function in ciliogenesis4, 5. Fibroblast growth factor (FGF) signalling regulates cilia length and function through ciliogenic transcription factor Foxj1 in diverse epithelia9. In zebrafish Kupffers vesicle (KV), both Wnt/-catenin and Notch pathway regulate Foxj1 expression and controls ciliogenesis10, 11. Components of the phosphatidylinositol signaling cascade also regulate cilia formation in zebrafish. This conclusion is based on observations that knockdown of inositol-pentakisphosphate 2-kinase (Ipk1) reduced cilia length and decreased the cilia beating frequency12. Our understanding of ciliogenesis regulation is, however, incomplete. Using zebrafish genetics and cultured human epithelial cells we reveal for the first time the functions of prostaglandin signaling in vertebrate ciliogenesis. RESULTS mutants display defective ciliogenesis In the course of a zebrafish genetic screen for mutations that affect organogenesis, we identified the ((in ciliogenesis, we visualized cilia formation in developing embryos. At 24 hour post-fertilization (hpf), zebrafish otic vesicles (OVs) contain two clusters of long tether cilia and many short cilia distributed throughout OVs (Fig. 1j). In contrast to wild-type OVs Xanomeline oxalate (Fig. 1j), mutant OVs lacked short cilia but had relatively normal tether cilia (Fig. 1k). At 96 hpf, cristae kinocilia in ear semicircular canals were lost in mutants (Fig. 1l, m). In Kupffers vesicle (KV), we observed cilia loss and length reduction in mutant embryos relative to wild-type (Fig. 1n, o; r, s). mutants also exhibited a loss of ependymal cell Xanomeline oxalate cilia in the spinal canal (Fig. 1p, q). However, mutants do not form kidney cysts (Fig. 1t, u), and the formation and growth of pronephric cilia are not affected in mutants either (Supplementary Fig. 1e, f). Open in a separate window Physique 1 mutants exhibit cilia loss and cilia-associated phenotypes(aCf) Lateral views showing a ventrally curved body (b), hydrocephalus (red arrow) (d) and three otoliths (red arrows) (f) in mutants compared to wild-type (wt) embryos at 72 hpf (a, c, e). (gCi) Cardiac-specific.