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
Objective: To investigate the inhibitory effect of apogossypolone (ApoG2) on prostate cancer cell line PC-3 in vivo, and explore its mechanism. Methods: The models of transplantation tumors in Balb/c nu/nu mice were e...Objective: To investigate the inhibitory effect of apogossypolone (ApoG2) on prostate cancer cell line PC-3 in vivo, and explore its mechanism. Methods: The models of transplantation tumors in Balb/c nu/nu mice were established via subcutaneous injection of PC-3 cells and the tumor-transplanted mice were divided into 4 groups: control group and three ApoG2 treatment groups, with 10 mice in each group. Volumes of the tumor were estimated every 2 d and the morphology of tumor tissues was observed. Immunohistochemistry was employed to observe the expression of Bcl-2, PCNA, CD31, caspase-3 and caspase-8 in tumor tissues. Results: ApoG2 (2.5 mg/kg-10 mg/kg) given intraperitoneally once a day can obviously inhibit the growth of subcutaneous prostatic carcinoma implant. The tumor volume decreased obviously when the treatment dosage was bigger than 5.0 mg/kg (P<0.01). Meanwhile, ApoG2 decreased the expression of PCNA and CD31, and enhanced the expression of caspases-3, caspase-8 in tumor tissues. Conclusion: ApoG2 exert an inhibitory effect on prostatic carcinoma possibly by inducing apoptosis and inhibiting tumor angiogenesis.展开更多
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.
文摘Objective: To investigate the inhibitory effect of apogossypolone (ApoG2) on prostate cancer cell line PC-3 in vivo, and explore its mechanism. Methods: The models of transplantation tumors in Balb/c nu/nu mice were established via subcutaneous injection of PC-3 cells and the tumor-transplanted mice were divided into 4 groups: control group and three ApoG2 treatment groups, with 10 mice in each group. Volumes of the tumor were estimated every 2 d and the morphology of tumor tissues was observed. Immunohistochemistry was employed to observe the expression of Bcl-2, PCNA, CD31, caspase-3 and caspase-8 in tumor tissues. Results: ApoG2 (2.5 mg/kg-10 mg/kg) given intraperitoneally once a day can obviously inhibit the growth of subcutaneous prostatic carcinoma implant. The tumor volume decreased obviously when the treatment dosage was bigger than 5.0 mg/kg (P<0.01). Meanwhile, ApoG2 decreased the expression of PCNA and CD31, and enhanced the expression of caspases-3, caspase-8 in tumor tissues. Conclusion: ApoG2 exert an inhibitory effect on prostatic carcinoma possibly by inducing apoptosis and inhibiting tumor angiogenesis.
