Ultrastructural analysis reveals striking differences of intercellular contact lengths in bovine embryos produced in vivo, in vitro and by somatic cell nuclear transfer
| Autor: | H Alm, Frank Becker, Wolfgang Tomek, Wilhelm Kanitz, Helmut Torner, Ludwig Jonas, R. Poehland, Sanjay Bhojwani |
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| Rok vydání: | 2007 |
| Předmět: |
Male
Cytoplasm Nuclear Transfer Techniques animal structures Cloning Organism Embryonic Development Fertilization in Vitro Biology Pregnancy In vivo Genetics medicine Animals Blastocyst Organelles Cloning Embryogenesis Embryo Cell Biology Blastomere Embryo Mammalian In vitro maturation Cell biology Intercellular Junctions medicine.anatomical_structure embryonic structures Somatic cell nuclear transfer Cattle Female Developmental Biology |
| Zdroj: | Molecular Reproduction and Development. 74:775-784 |
| ISSN: | 1098-2795 1040-452X |
| DOI: | 10.1002/mrd.20668 |
| Popis: | Cellular coherence and communication, thus cell-to-cell contact is an indispensable premise to sustain the formation of complex, multi-cellular organisms. We have analyzed intercellular contact lengths in NT-cloned bovine embryos compared to the in vivo or in vitro produced counterparts. Therefore, ultrastructural analysis was carried out by transmission electron microscopy (TEM) at the 8-cell and blastocyst stage of development. To obtain embryos generated in vivo, oviducts of superovulated cows were flushed 3 days after insemination, subsequent to slaughter. Standard in vitro maturation (IVM) and -fertilization (IVF) were utilized to obtain in vitro embryos. Cloned embryos by somatic nuclear transfer were produced by the handmade cloning (HMC™) procedure. The points of apposition/focal contact points (CPs) between the blastomeres were of the shortest order in cloned embryos (236 ± 135 nm) and of highest order in the in vivo produced embryos (2,085 ± 1,540 nm), although no significant differences regarding the blastomere sizes in the various groups of 8-cell embryos could be established. In summary, the CP lengths in case of in vitro and in vivo 8-cell embryos were, on an average, five or nine times longer, respectively, than in the case of the cloned embryos. These differences of CP lengths vanished in embryos reaching the blastocyst stage of embryonic development in all the three groups of embryos. The observed differences of intercellular contact length at distinct stages of embryonic development could be responsible for differences in intercellular communication between the blastomeres at the beginning of cellular differentiation. These may be one reason for the lower developmental competence of cloned (NT) embryos. Mol. Reprod. Dev. 74: 775–784, 2007. © 2006 Wiley-Liss, Inc. |
| Databáze: | OpenAIRE |
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