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The anaphase promoting complex/cyclosome (APC/C) and its cofactors CDH1 and CDC20 regulate the accumulation/degradation of CCNB1 during mouse oocyte meiotic maturation. Generally, the CCNB1 degradation mediated by APC/CCDC20 activity is essential for the transition from metaphase to anaphase. Here, by using siRNA and mRNA microinjection, as well as time‐lapse live imaging, we showed that Septin 9, which mediates the binding of septins to microtubules, is critical for oocyte meiotic cell cycle progression. The oocytes were arrested at the MI stage and the connection between chromosome kinetochores and spindle microtubules was disrupted after Septin 9 depletion. As it is well known that spindle assembly checkpoint (SAC) is an important regulator of the MI‐AI transition, we thus detected the SAC activity and the expression of CDC20 and CCNB1 which were the downstream proteins of SAC during this critical period. The signals of Mad1 and BubR1 still remained on the kinetochores of chromosomes in Septin 9 siRNA oocytes at 9.5 h of in vitro culture when most control oocytes entered anaphase I. The expression of CCNB1 did not decrease and the expression of CDC20 did not increase at 9.5 h in Septin 9 siRNA oocytes. Microinjection of mRNA encoding Septin 9 or CDC20 could partially rescue MI arrest caused by Septin 9 siRNA. These results suggest that Septin 9 is required for meiotic MI‐AI transition by regulating the kinetochore‐microtubule connection and SAC protein localization on kinetochores, whose effects are transmitted to APC/CCDC20 activity and CCNB1 degradation in mouse oocytes. [ABSTRACT FROM AUTHOR]

BACKGROUND: Maternal obesity has adverse effects on oocyte quality, embryo development, and the health of the offspring. OBJECTIVES: To understand the underlying mechanisms responsible for the negative effects of maternal obesity, we investigated the DNA methylation status of several imprinted genes and metabolism-related genes. METHODS: Using a high-fat-diet (HFD)-induced mouse model of obesity, we analyzed the DNA methylation of several imprinted genes and metabolism-related genes in oocytes from control and obese dams and in oocytes and liver from their offspring. Analysis was performed using combined bisulfite restriction analysis (COBRA) and bisulfite sequencing. RESULTS: DNA methylation of imprinted genes in oocytes was not altered in either obese dams or their offspring; however, DNA methylation of metabolism-related genes was changed. In oocytes of obese mice, the DNA methylation level of the leptin (Lep) promoter was significantly increased and that of the Ppar-α promoter was reduced. Increased methylation of Lep and decreased methylation of Ppar-α was also observed in the liver of female offspring from dams fed the high-fat diet (OHFD). mRNA expression of Lep and Ppar-α was also significantly altered in the liver of these OHFD. In OHFD oocytes, the DNA methylation level of Ppar-α promoter was increased. CONCLUSIONS: Our results indicate that DNA methylation patterns of several metabolism-related genes are changed not only in oocytes of obese mice but also in oocytes and liver of their offspring. These data may contribute to the understanding of adverse effects of maternal obesity on reproduction and health of the offspring., Introduction The World Health Organization has reported that obesity, defined as abnormal or excessive fat accumulation that may impair health, has nearly doubled since 1980, and nearly 300 million women [...]

Since The Government Information Disclosure Regulations took effect, people's application for the access to the government financial information has attracted wide attention and aroused lots of public responses. These actions, which are done in the name of individuals and carry symbolic value rather than having direct and immediate consequences, are mainly a test of the effect of the above mentioned regulations, putting pressure on the government and its officials to enhance the openness of its information. The symbolic nature of these actions indicates that there are great barriers to publicizing government information; embodies the strategies and multiple appeals of the applicants; and also has multiple meanings of expressing civil rights, pinpointing the government accountability and regulating the relations between government and citizens. In the process of applying for the disclosure of government information, citizens have enough incentive to push for the openness of government information, and the application practice of citizens also promotes institutional change. [ABSTRACT FROM AUTHOR]

The anaphase promoting complex/cyclosome (APC/C) and its cofactors CDH1 and CDC20 regulate the accumulation/degradation of CCNB1 during mouse oocyte meiotic maturation. Generally, the CCNB1 degradation mediated by APC/C CDC20 activity is essential for the transition from metaphase to anaphase. Here, by using siRNA and mRNA microinjection, as well as time-lapse live imaging, we showed that Septin 9, which mediates the binding of septins to microtubules, is critical for oocyte meiotic cell cycle progression. The oocytes were arrested at the MI stage and the connection between chromosome kinetochores and spindle microtubules was disrupted after Septin 9 depletion. As it is well known that spindle assembly checkpoint (SAC) is an important regulator of the MI-AI transition, we thus detected the SAC activity and the expression of CDC20 and CCNB1 which were the downstream proteins of SAC during this critical period. The signals of Mad1 and BubR1 still remained on the kinetochores of chromosomes in Septin 9 siRNA oocytes at 9.5 h of in vitro culture when most control oocytes entered anaphase I. The expression of CCNB1 did not decrease and the expression of CDC20 did not increase at 9.5 h in Septin 9 siRNA oocytes. Microinjection of mRNA encoding Septin 9 or CDC20 could partially rescue MI arrest caused by Septin 9 siRNA. These results suggest that Septin 9 is required for meiotic MI-AI transition by regulating the kinetochore-microtubule connection and SAC protein localization on kinetochores, whose effects are transmitted to APC/C CDC20 activity and CCNB1 degradation in mouse oocytes., (© 2022 The Authors. Cell Proliferation published by Beijing Institute for Stem Cell and Regenerative Medicine and John Wiley & Sons Ltd.)

As a serine/threonine kinase, NIMA-related kinases (NEKs) play important roles in the regulation of cell cycle, and involve in several cellular activities such as centrosome separation, spindle assembly, chromatin condensation, nuclear envelope breakdown, spindle assembly checkpoint signaling, cytokinesis, cilia formation and DNA damage response. In this review, we summarize the component, structural characteristics and functions of NEK family in mitosis and meiosis based on the relevant researches in recent years, providing a reference for the further study on the roles of NEKs in the regulation of cell cycle and a theoretical basis for the clinical diagnosis and treatment of tumors.

Somatic cell nuclear transfer (SCNT) has great potential for agricultural applications, generation of medical model animals, transgenic farm animals or generating human embryonic stem cells for treatment of human diseases. Cloned animals derived from somatic cells have been generated in several mammal species, but there are still some unsolved problems with current cloning technology, for example, the low efficiency of animal cloning and the abnormal development of cloned animals. One critical factor of these developmental failures of cloned embryos is the aberrant epigenetic reprogramming. This review focuses on DNA methylation and histone modifications and the relationship between these two epigenetic modifications and the development of cloned embryos. Understanding the mechanisms of epigenetic regulation will be useful to solve the technical problems of SCNT and enable better applications of this technology.

Adult somatic cell cloned calves were produced by somatic cell nuclear transfer prepared by fusion of cultured ear fibroblast from a Holstein cow into enucleated oocytes of Luxi Yellow cow. In order to determinate the source of mitochondrial DNA of cloned calves, we designed the breed-specific PCR primers by aligning the known D-loop sequences of Bos taurus and analyzed the displacement loop sequences of five live cloned calves by breed-specific primers PCR. The results demonstrated that mtDNA originated from Holstein breed and that from Luxi breed co-exist in all five live calves., (Copyright 2004 Wiley-Liss, Inc.)

Following the production of cloned sheep, mice, goats, pigs, cats, rabbits and argali from somatic cells, the cellular and molecular biological tests of cloned animals and early embryos turn to be more important. In this review, chromosome analysis, nuclear DNA analysis, mitochondrial DNA analysis and telomeric DNA analysis that are applied in the detection of cloned mammal and early embryos are described.

It is the point at issue in intraspecies nuclear transfer whether quiescence is necessary for development of nuclear transfer reconstructed embryos. In the interspecies nuclear transfer, some reports have proved that quiescent cell is able to support preimplantation development of the interspecies reconstructed embryos. Are non-quiescent cells able to support preimplantation development of the interspecies reconstructed embryos? We used non-quiescent somatic cells from C57BL/6 mice and giant pandas as donors to transfer into enucleated rabbit oocytes. After electrofusion (the electrofusion rates were 62.2% and 71.6%, respectively) and electrical activation, 5.1% of those mouse-rabbit reconstructed embryos developed to blastocyst in vitro, and 4.2% of panda-rabbit reconstructed embryos developed to blastocyst after transferring into ligated rabbit oviduct. These results indicate that non-quiescent cell from C57BL/6 mouse and giant panda could be dedifferentiated in enucleated rabbit oocytes and support early embryo development.