以广东温氏集团培育的黄羽肉鸡种蛋胚胎为研究对象,并以与人和小鼠胚胎发育相关的胰岛素样生长因子2受体(insulin-like growth factor type II receptor,IGF2R)基因为候选基因,进行了SNP位点的筛选和多态性的检测,探讨了IGF2R的变异对...以广东温氏集团培育的黄羽肉鸡种蛋胚胎为研究对象,并以与人和小鼠胚胎发育相关的胰岛素样生长因子2受体(insulin-like growth factor type II receptor,IGF2R)基因为候选基因,进行了SNP位点的筛选和多态性的检测,探讨了IGF2R的变异对胚胎死亡的影响。在IGF2R第34外显子中发现2个SNP位点,对具有AlwNⅠ酶切位点的SNP位点进行了PCR-RFLP检测,分析了胚胎IGF2R的SNP位点PCR-RFLPs基因型在死亡和正常发育胚胎中分布特征。经2χ检验,鸡基因IGF2R第34外显子AlwNⅠ-RFLP基因型在死亡和正常发育胚胎中存在显著差异,在死亡的胚胎中基因型AT的频率(0.326)显著地高于正常发育胚胎的频率(0.077)。展开更多
Somatic cell nuclear transfer （SCNT） and parthenogenesis are alternative forms of reproduction and development, building new life cycles on differentiated somatic cell nuclei and duplicated maternal chromatin, respe...Somatic cell nuclear transfer （SCNT） and parthenogenesis are alternative forms of reproduction and development, building new life cycles on differentiated somatic cell nuclei and duplicated maternal chromatin, respectively. In the preceding paper （Sun F, et al., Cell Res 2007; 17：117-134.）, we showed that an ＂erase-and-rebuild＂ strategy is used in normal development to transform the maternal gene expression profile to a zygotic one. Here, we investigate if the same strategy also applies to SCNT and parthenogenesis. The relationship between chromatin and chromatin factors （CFs） during SCNT and parthenogenesis was examined using immunochemical and GFP-fusion protein assays. Results from these studies indicated that soon after nuclear transfer, a majority of CFs dissociated from somatic nuclei and were redistributed to the cytoplasm of the egg. The erasure process in oogenesis is recaptured during the initial phase in SCNT. Most CFs entered pseudo-pronuclei shortly after their formation. In parthenogenesis, all parthenogenotes underwent normal oogenesis, and thus had removed most CFs from chromosomes before the initiation of development. The CFs were subsequently re-associated with female pronuclei in time and sequence similar to that in fertilized embryos. Based on these data, we conclude that the ＂erase-and-rebuild＂ process observed in normal development also occurs in SCNT and in parthenogenesis, albeit in altered fashions. The process is responsible for transcription reprogramming in these procedures. The ＂erase＂ process in SCNT is compressed and the efficiency is compromised, which likely contribute to the developmental defects often observed in nuclear transfer （nt） embryos. Furthermore, results from this study indicated that the cytoplasm of an egg contains most, if not all, essential components for assembling the zygotic program and can assemble them onto appropriate diploid chromatin of distinct origins.展开更多
文摘以广东温氏集团培育的黄羽肉鸡种蛋胚胎为研究对象,并以与人和小鼠胚胎发育相关的胰岛素样生长因子2受体(insulin-like growth factor type II receptor,IGF2R)基因为候选基因,进行了SNP位点的筛选和多态性的检测,探讨了IGF2R的变异对胚胎死亡的影响。在IGF2R第34外显子中发现2个SNP位点,对具有AlwNⅠ酶切位点的SNP位点进行了PCR-RFLP检测,分析了胚胎IGF2R的SNP位点PCR-RFLPs基因型在死亡和正常发育胚胎中分布特征。经2χ检验,鸡基因IGF2R第34外显子AlwNⅠ-RFLP基因型在死亡和正常发育胚胎中存在显著差异,在死亡的胚胎中基因型AT的频率(0.326)显著地高于正常发育胚胎的频率(0.077)。
文摘Somatic cell nuclear transfer （SCNT） and parthenogenesis are alternative forms of reproduction and development, building new life cycles on differentiated somatic cell nuclei and duplicated maternal chromatin, respectively. In the preceding paper （Sun F, et al., Cell Res 2007; 17：117-134.）, we showed that an ＂erase-and-rebuild＂ strategy is used in normal development to transform the maternal gene expression profile to a zygotic one. Here, we investigate if the same strategy also applies to SCNT and parthenogenesis. The relationship between chromatin and chromatin factors （CFs） during SCNT and parthenogenesis was examined using immunochemical and GFP-fusion protein assays. Results from these studies indicated that soon after nuclear transfer, a majority of CFs dissociated from somatic nuclei and were redistributed to the cytoplasm of the egg. The erasure process in oogenesis is recaptured during the initial phase in SCNT. Most CFs entered pseudo-pronuclei shortly after their formation. In parthenogenesis, all parthenogenotes underwent normal oogenesis, and thus had removed most CFs from chromosomes before the initiation of development. The CFs were subsequently re-associated with female pronuclei in time and sequence similar to that in fertilized embryos. Based on these data, we conclude that the ＂erase-and-rebuild＂ process observed in normal development also occurs in SCNT and in parthenogenesis, albeit in altered fashions. The process is responsible for transcription reprogramming in these procedures. The ＂erase＂ process in SCNT is compressed and the efficiency is compromised, which likely contribute to the developmental defects often observed in nuclear transfer （nt） embryos. Furthermore, results from this study indicated that the cytoplasm of an egg contains most, if not all, essential components for assembling the zygotic program and can assemble them onto appropriate diploid chromatin of distinct origins.
