Identification and characterization of Caenorhabditis elegans gamma-tubulin in dividing cells and differentiated tissues

gamma -Tubulin is an essential component of the microtubule-nucleation mach inery and therefore plays a crucial role during mitosis. To gain further in sights into the function of this protein in the events that take place duri ng embryogenesis and differentiation, we carried out detailed studies on ga mma -tubulin during all the developmental stages of Caenorhabditis elegans. We identified the gamma -tubulin gene from this organism and analyzed the localization of the protein by both immunofluorescence and GFP reporter con struct. We show that gamma -tubulin association with the centrosome is high ly dynamic in mitotic cells, being massively recruited at prophase and rele ased at anatelophase. This accumulation in mitotic centrosomes is dramatic during the first embryonic divisions. We provide the first description of t he morphological changes at the centrosome level during the orientation of the mitotic spindle and the flattening of the posterior aster. Loss of func tion of the gamma -tubulin gene by RNAi induces a strong polyploidization o f mitotic germ cells and embryos, but does not affect meiosis and pronuclea r migration. In addition, we demonstrate the prominent redistribution of ga mma -tubulin in adults at basal bodies of amphid and phasmid neurons, and a t the apical membrane of polarized intestinal cells.