Satoshi Kamimura

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Mouse spermatogonial stem cells (SSCs) can be cultured for multiplication and maintained for long periods while preserving their spermatogenic ability. Although the cultured SSCs, named germline stem (GS) cells, are targets of genome modification, this process remains technically difficult. In the present study, we tested TALEN and double-nicking(More)
STUDY QUESTION Is the poor development of embryos generated from round spermatid injection (ROSI) in humans and animals associated with abnormal active DNA demethylation? SUMMARY ANSWER A significant proportion of ROSI-derived embryos failed to undergo active DNA demethylation. WHAT IS KNOWN ALREADY Active DNA demethylation is initiated by the(More)
Substantial proportions of mammalian genomes comprise repetitive elements including endogenous retrotransposons. Although these play diverse roles during development, their appropriate silencing is critically important in maintaining genomic integrity in the host cells. The major mechanism for retrotransposon silencing is DNA methylation, but the wave of(More)
Whereas cloning mammals by direct somatic cell nuclear transfer has been successful using a wide range of donor cell types, neurons from adult brain remain "unclonable" for unknown reasons. Here, using a combination of two epigenetic approaches, we examined whether neurons from adult mice could be cloned. First, we used a specific antibody to discover cell(More)
In mice, the establishment of paternal genomic imprinting in male germ cells starts at midgestation, as suggested by DNA methylation analyses of differentially methylated regions (DMRs). However, this information is based on averages from mixed populations of germ cells, and the DNA methylation pattern might not always provide a full representation of(More)
During mouse development, imprinted X chromosome inactivation (XCI) is observed in preimplantation embryos and is inherited to the placental lineage, whereas random XCI is initiated in the embryonic proper. Xist RNA, which triggers XCI, is expressed ectopically in cloned embryos produced by somatic cell nuclear transfer (SCNT). To understand these(More)
In mice, one of the major epigenetic errors associated with somatic cell nuclear transfer (SCNT) is ectopic expression of Xist during the preimplantation period in both sexes. We found that this aberrant Xist expression could be impeded by deletion of Xist from the putative active X chromosome in donor cells. In male clones, it was also found that prior(More)
Somatic cell nuclear transfer (SCNT) is a unique technology that produces cloned animals from single cells. It is desirable from a practical viewpoint that donor cells can be collected noninvasively and used readily for nuclear transfer. The present study was undertaken to determine whether peripheral blood cells freshly collected from living mice could be(More)
Although mammalian cloning by somatic cell nuclear transfer (SCNT) has been established in various species, the low developmental efficiency has hampered its practical applications. Treatment of SCNT-derived embryos with histone deacetylase (HDAC) inhibitors can improve their development, but the underlying mechanism is still unclear. To address this(More)
A new synthesis of α-quaternary alkynyl amino esters and allenoates was developed utilizing umpolung N-addition to β,γ-alkynyl α-imino esters followed by regioselective acylation. The reaction exhibits broad substrate generality and unique regioselectivity. Moreover, synthesis of α-quaternary alkynyl amino esters was also carried out via oxidation of the(More)