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BackgroundMutations in microtubule-regulating genes are associated with disorders of neuronal migration and microcephaly. Regulation of centriole length has been shown to underlie the pathogenesis of certain ciliopathy phenotypes. Using a next-generation sequencing approach, we identified mutations in a novel centriolar disease gene in a kindred with an embryonic lethal ciliopathy phenotype and in a patient with primary microcephaly.Methods and resultsWhole exome sequencing data from a non-consanguineous Caucasian kindred exhibiting mid-gestation lethality and ciliopathic malformations revealed two novel non-synonymous variants in CENPF, a microtubule-regulating gene. All four affected fetuses showed segregation for two mutated alleles [IVS5-2A>C, predicted to abolish the consensus splice-acceptor site from exon 6; c.1744G>T, p.E582X]. In a second unrelated patient exhibiting microcephaly, we identified two CENPF mutations [c.1744G>T, p.E582X; c.8692 C>T, p.R2898X] by whole exome sequencing. We found that CENP-F colocalised with Ninein at the subdistal appendages of the mother centriole in mouse inner medullary collecting duct cells. Intraflagellar transport protein-88 (IFT-88) colocalised with CENP-F along the ciliary axonemes of renal epithelial cells in age-matched control human fetuses but did not in truncated cilia of mutant CENPF kidneys. Pairwise co-immunoprecipitation assays of mitotic and serum-starved HEKT293 cells confirmed that IFT88 precipitates with endogenous CENP-F.ConclusionsOur data identify CENPF as a new centriolar disease gene implicated in severe human ciliopathy and microcephaly related phenotypes. CENP-F has a novel putative function in ciliogenesis and cortical neurogenesis.

Research was conducted to prove that pericentrin and gamma-tubulin form a protein complex and are organized into a novel lattice at the centrosome. Extracts were prepared from Xenopus eggs, gel filtration, sucrose gradient sedimentation and coimmunoprecipitation examination revealed that proteins belonged to a large complex. An improved immunofluorescence technique determined the three-dimensional organization of the centrosome-associated fraction of the proteins. Results also indicate that pericentrin and gamma-tubulin are organized into a lattice at the centrosome.

Pericentrin, a centrosome protein has a central alpha-helical region accompanied by nonhelical domains at the sides. It is present with gamma-tubulin at microtubule nucleation sites. It is an integral part of the composition of microtubule nucleating material, and its localization is independent of centrioles and microtubules. Pericentrin contributes to the centrosome's ability to nucleate microtubule assembly.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cell.2009.01.028 Byline: Chun-Ting Chen (1), Stephen Doxsey (1) Abstract: Chromosome segregation and cytokinesis must be tightly coordinated to ensure that chromosomes are accurately partitioned between dividing cells. In this issue, report that Aurora B kinase promotes proper chromosome segregation by delaying abscission when chromatin is trapped between dividing cells. Author Affiliation: (1) University of Massachusetts Medical School, Program in Molecular Medicine, Worcester, MA 01655, USA

The study is conducted to show that centriolin interacts with proteins of vesicle-targeting exocyst complexes and vesicle-fusion SNARE complexes. Centriolin anchors protein complexes required for vesicle targeting and fusion and integrates membrane-vesicle fusion with abscission.