Nomura Jun, Maruyama Masayoshi, Katano Miyuki, Kato Hidemasa, Zhang Jiaxing, Masui Shinji, Mizuno Yosuke, Okazaki Yasushi, Nishimoto Masazumi, Okuda Akihiko
Division of Developmental Biology, Research Center for Genomic Medicine, Saitama Medical University, Yamane Hidaka, Saitama, Japan.
Stem Cells. 2009 May;27(5):1066-76. doi: 10.1002/stem.44.
Stem cells have the remarkable ability to self-renew and to generate multiple cell types. Nucleostemin is one of proteins that are enriched in many types of stem cells. Targeted deletion of nucleostemin in the mouse results in developmental arrest at the implantation stage, indicating that nucleostemin is crucial for early embryogenesis. However, the molecular basis of nucleostemin function in early mouse embryos remains largely unknown, and the role of nucleostemin in tissue stem cells has not been examined by gene targeting analyses due to the early embryonic lethality of nucleostemin null animals. To address these questions, we generated inducible nucleostemin null embryonic stem (ES) cells in which both alleles of nucleostemin are disrupted, but nucleostemin cDNA under the control of a tetracycline-responsive transcriptional activator is introduced into the Rosa26 locus. We show that loss of nucleostemin results in reduced cell proliferation and increased apoptosis in both ES cells and ES cell-derived neural stem/progenitor cells. The reduction in cell viability is much more profound in ES cells than in neural stem/progenitor cells, an effect that is mediated at least in part by increased induction and accumulation of p53 and/or activated caspase-3 in ES cells than in neural stem/progenitor cells.
干细胞具有自我更新和产生多种细胞类型的非凡能力。核仁素是在多种类型干细胞中富集的蛋白质之一。在小鼠中靶向缺失核仁素会导致着床阶段的发育停滞，这表明核仁素对早期胚胎发育至关重要。然而，核仁素在早期小鼠胚胎中发挥功能的分子基础仍 largely 未知，并且由于核仁素基因敲除动物的早期胚胎致死性，尚未通过基因靶向分析来研究核仁素在组织干细胞中的作用。为了解决这些问题，我们生成了诱导型核仁素基因敲除胚胎干细胞（ES 细胞），其中核仁素的两个等位基因均被破坏，但在四环素反应性转录激活因子控制下的核仁素 cDNA 被引入 Rosa26 位点。我们表明，核仁素的缺失导致 ES 细胞和 ES 细胞衍生的神经干细胞/祖细胞中的细胞增殖减少和凋亡增加。ES 细胞中细胞活力的降低比神经干细胞/祖细胞中更为显著，这种效应至少部分是由 ES 细胞中 p53 和/或活化的 caspase-3 的诱导和积累增加介导的，而不是神经干细胞/祖细胞。
