a highly conserved poc1 protein characterized in embryos of the hydrozoan clytia hemisphaerica localization and functional studies一个高度保守的poc1胚胎蛋白质特征的水螅虫类的clytia hemisphaerica定位和功能的研究.pdfVIP

A Highly Conserved Poc1 Protein Characterized in Embryos of the Hydrozoan Clytia hemisphaerica: Localization and Functional Studies ´ Cecile Fourrage, Sandra Chevalier, Evelyn Houliston* ´ Universite Pierre et Marie Curie and CNRS, Developmental Biology Unit, Villefranche-sur-Mer, France Abstract Poc1 (Protein of Centriole 1) proteins are highly conserved WD40 domain-containing centriole components, well characterized in the alga Chlamydomonas, the ciliated protazoan Tetrahymena, the insect Drosophila and in vertebrate cells including Xenopus and zebrafish embryos. Functions and localizations related to the centriole and ciliary axoneme have been demonstrated for Poc1 in a range of species. The vertebrate Poc1 protein has also been reported to show an additional association with mitochondria, including enrichment in the specialized ‘‘germ plasm’’ region of Xenopus oocytes. We have identified and characterized a highly conserved Poc1 protein in the cnidarian Clytia hemisphaerica. Clytia Poc1 mRNA was found to be strongly expressed in eggs and early embryos, showing a punctate perinuclear localization in young oocytes. Fluorescence-tagged Poc1 proteins expressed in developing embryos showed strong localization to centrioles, including basal bodies. Anti-human Poc1 antibodies decorated mitochondria in Clytia, as reported in human cells, but failed to recognise endogenous or fluorescent-tagged Clytia Poc1. Injection of specific morpholino oligonucleotides into Clytia eggs prior to fertilization to repress Poc1 mRNA translation interfered with cell division from the blastula stage, likely corresponding to when neosynthesis normally takes over from maternally supplied protein. Cell cycle lengthening and arrest were observed, pheno