title: Function of donor cell centrosome in intraspecies and interspecies nuclear transfer embryos.
abstract: Centrosomes, the main microtubule-organizing centers (MTOCs) in most animal cells, are important for many cellular activities such as assembly of the mitotic spindle, establishment of cell polarity, and cell movement. In nuclear transfer (NT), MTOCs that are located at the poles of the meiotic spindle are removed from the recipient oocyte, while the centrosome of the donor cell is introduced. We used mouse MII oocytes as recipients, mouse fibroblasts, rat fibroblasts, or pig granulosa cells as donor cells to construct intraspecies and interspecies nuclear transfer embryos in order to observe centrosome dynamics and functions. Three antibodies against centrin, gamma-tubulin, and NuMA, respectively, were used to stain the centrosome. Centrin was not detected either at the poles of transient spindles or at the poles of first mitotic spindles. gamma-tubulin translocated into the two poles of the transient spindles, while no accumulated gamma-tubulin aggregates were detected in the area adjacent to the two pseudo-pronuclei. At first mitotic metaphase, gamma-tubulin was translocated to the spindle poles. The distribution of gamma-tubulin was similar in mouse intraspecies and rat-mouse interspecies embryos. The NuMA antibody that we used can recognize porcine but not murine NuMA protein, so it was used to trace the NuMA protein of donor cell in reconstructed embryos. In the pig-mouse interspecies reconstructed embryos, NuMA concentrated between the disarrayed chromosomes soon after activation and translocated to the transient spindle poles. NuMA then immigrated into pseudo-pronuclei. After pseudo-pronuclear envelope breakdown, NuMA was located between the chromosomes and then translocated to the spindle poles of first mitotic metaphase. gamma-tubulin antibody microinjection resulted in spindle disorganization and retardation of the first cell division. NuMA antibody microinjection also resulted in spindle disorganization. Our findings indicate that (1) the donor cell centrosome, defined as pericentriolar material surrounding a pair of centrioles, is degraded in the 1-cell reconstituted embryos after activation; (2) components of donor cell centrosomes contribute to the formation of the transient spindle and normal functional mitotic spindle, although the contribution of centrosomal material stored in the recipient ooplasm is not excluded; and (3) components of donor cell centrosomes involved in spindle assembly may not be species-specific.
authors.affiliation: State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Zhi-Sheng
authors.initials: ZS
authors.lastname: Zhong
authors.forename: Gang
authors.initials: G
authors.lastname: Zhang
authors.forename: Xiao-Qian
authors.initials: XQ
authors.lastname: Meng
authors.forename: Yan-Ling
authors.initials: YL
authors.lastname: Zhang
authors.forename: Da-Yuan
authors.initials: DY
authors.lastname: Chen
authors.forename: Heide
authors.initials: H
authors.lastname: Schatten
authors.forename: Qing-Yuan
authors.initials: QY
authors.lastname: Sun
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D034961:Antigens, Nuclear; D002135:Calcium-Binding Proteins / Q000032:analysis / Q000378:metabolism; D018797:Cell Cycle Proteins; D002459:Cell Fusion; D018385:Centrosome / Q000378:metabolism / Q000502:physiology* / Q000637:transplantation; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis / Q000378:metabolism; D004622:Embryo, Mammalian / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D006107:Granulosa Cells / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D006367:HeLa Cells / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D006801:Humans; D051379:Mice; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins / Q000032:analysis / Q000378:metabolism; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D008941:Spindle Apparatus / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D013552:Swine; D014183:Transplantation, Heterologous; D014184:Transplantation, Homologous; D014404:Tubulin / Q000032:analysis / Q000276:immunology / Q000378:metabolism
chemical_list: D000906:Antibodies; D034961:Antigens, Nuclear; D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; C050045:NUMA1 protein, human; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins; D014404:Tubulin; C056608:caltractin