Publications by authors named "S Torikai-Nishikawa"

Myst family genes encode lysine acetyltransferases that mainly mediate histone acetylation to control transcription, DNA replication and DNA damage response. They form tetrameric complexes with PHD-finger proteins (Brpfs or Jades) and small non-catalytic subunits Ing4/5 and Meaf6. Although all the components of the complex are well-conserved from yeast to mammals, the function of Meaf6 and its homologs has not been elucidated in any species.

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Background: Stable expression of transgenes is an important technique to analyze gene function. Various drug resistance genes, such as neo, pac, hph, zeo, bsd, and hisD, have been equally used as selection markers to isolate a transfectant without considering their dose-dependent characters.

Results: We quantitatively measured the variation of transgene expression levels in mouse embryonic stem (mES) cells, using a series of bi-cistronic expression vectors that contain Egfp expression cassette linked to each drug resistant gene via IRES with titration of the selective drugs, and found that the transgene expression levels achieved in each system with this vector design are in order, in which pac and zeo show sharp selection of transfectants with homogenously high expression levels.

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Quiescence is an important feature distinguishing stem cells (SCs) from other compartments for most SC systems. Evidence suggests that the quiescent state is directed by external cues expressed in the presumptive microenvironment, the niche, although the cellular and molecular nature of the niche remains obscure in most SC systems. Our group has been addressing this question using the melanocyte (MC) as a model, because MC SCs (MSCs) and other compartments are distinguished by their location in the hair follicle, the former in the bulge and the other in the hair matrix.

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Preparation of specific lineages at high purities from embryonic stem (ES) cells requires both selective culture conditions and markers to guide and monitor the differentiation. In this study, we distinguished definitive and visceral endoderm by using a mouse ES cell line that bears the gfp and human IL2R alpha (also known as CD25) marker genes in the goosecoid (Gsc) and Sox17 loci, respectively. This cell line allowed us to monitor the generation of Gsc+ Sox17+ definitive endoderm and Gsc- Sox17+ visceral endoderm and to define culture conditions that differentially induce definitive and visceral endoderm.

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