Clone- and Gene-Specific Aberrations of Parental Imprinting in Human Induced Pluripotent Stem Cells
Clone- and Gene-Specific Aberrations of Parental Imprinting in Human Induced Pluripotent Stem Cells
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DOI：
10.1002/stem.205
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发表时间：
2009-11-01
期刊：
影响因子：
5.2
通讯作者：
Benvenisty, Nissim
中科院分区：
文献类型：
--
作者：
Pick, Marjorie;Stelzer, Yonatan;Benvenisty, Nissim
基因组印记是一种表观遗传现象，即基因以单等位基因的方式表达，这是母系或父系遗传的。印迹基因的表达已经在人类胚胎干细胞（ES）中进行了研究，这些细胞显示出相当程度的基因组印迹稳定性。最近，人类体细胞被重新编程为多能状态，使用各种确定的因素。这些诱导多能干细胞（iPS）被认为在研究遗传疾病方面具有巨大的潜力，并且是患者特异性干细胞的来源。因此，研究这些细胞中印迹基因的表达是很重要的。我们检测了几种iPS细胞系中各种印迹基因的等位基因表达，发现了四个基因的多态性。在分析了这些基因的亲本特异性表达后，我们在iPS细胞系中观察到总体正常的单等位基因表达。然而，我们在一个iPS细胞系中发现了H19基因的双等位表达，在另一个iPS细胞系中发现了KCNQ10T1基因的双等位表达。我们进一步分析了H19基因启动子区域的DNA甲基化水平，发现显示双等位基因表达的细胞系经历了广泛的DNA去甲基化。此外，我们通过DNA微阵列分析研究了多种人类iPS细胞系的印迹基因表达模式，并将表达模式分为三组：(a)在iPS细胞中表现出显著稳定表达水平的基因，(b)在人类胚胎干细胞和iPS细胞中表现出相当程度的表达差异的基因，以及(c)与人类胚胎干细胞相比，在某些人类iPS细胞系中表现出异常表达水平的基因。一般来说，iPS细胞具有相当稳定的印迹基因表达。然而，我们发现有相当数量的细胞系存在印迹基因的异常表达，因此我们认为，如果要用于研究遗传疾病或用于再生医学，应该对每个细胞系进行印迹基因检测。干细胞2009；27日:2686 - 2690
Genomic imprinting is an epigenetic phenomenon whereby genes are expressed in a monoallelic manner, which is inherited either maternally or paternally. Expression of imprinted genes has been examined in human embryonic stem (ES) cells, and the cells show a substantial degree of genomic imprinting stability. Recently, human somatic cells were reprogrammed to a pluripotent state using various defined factors. These induced pluripotent stem (iPS) cells are thought to have a great potential for studying genetic diseases and to be a source of patient-specific stem cells. Thus, studying the expression of imprinted genes in these cells is important. We examined the allelic expression of various imprinted genes in several iPS cell lines and found polymorphisms in four genes. After analyzing parent-specific expression of these genes, we observed overall normal monoallelic expression in the iPS cell lines. However, we found biallelic expression of the H19 gene in one iPS cell line and biallelic expression of the KCNQ10T1 gene in another iPS cell line. We further analyzed the DNA methylation levels of the promoter region of the H19 gene and found that the cell line that showed biallelic expression had undergone extensive DNA demethylation. Additionally we studied the imprinting gene expression pattern of multiple human iPS cell lines via DNA microarray analyses and divided the pattern of expression into three groups: (a) genes that showed significantly stable levels of expression in iPS cells, (b) genes that showed a substantial degree of variability in expression in both human ES and iPS cells, and (c) genes that showed aberrant expression levels in some human iPS cell lines, as compared with human ES cells. In general, iPS cells have a rather stable expression of their imprinted genes. However, we found a significant number of cell lines with abnormal expression of imprinted genes, and thus we believe that imprinted genes should be examined for each cell line if it is to be used for studying genetic diseases or for the purpose of regenerative medicine. STEM CELLS 2009; 27: 2686-2690