Bijvoet Center for Biomolecular Research, Utrecht Institute for Pharmaceutical Sciences, University, The Netherlands.
EMBO J. 2012 Jun 12;31(14):3079-91. doi: 10.1038/emboj.2012.166.
Two types of stem cells are currently defined in small intestinal crypts: cycling crypt base columnar (CBC) cells and quiescent '+4' cells. Here, we combine transcriptomics with proteomics to define a definitive molecular signature for Lgr5(+) CBC cells. Transcriptional profiling of FACS-sorted Lgr5(+) stem cells and their daughters using two microarray platforms revealed an mRNA stem cell signature of 384 unique genes. Quantitative mass spectrometry on the same cell populations identified 278 proteins enriched in intestinal stem cells. The mRNA and protein data sets showed a high level of correlation and a combined signature of 510 stem cell-enriched genes was defined. Spatial expression patterns were further characterized by mRNA in-situ hybridization, revealing that approximately half of the genes were expressed in a gradient with highest levels at the crypt bottom, while the other half was expressed uniquely in Lgr5(+)stem cells. Lineage tracing using a newly established knock-in mouse for one of the signature genes, Smoc2, confirmed its stem cell specificity. Using this resource, we find-and confirm by independent approaches-that the proposed quiescent/'+4' stem cell markers Bmi1, Tert, Hopx and Lrig1 are robustly expressed in CBC cells.
循环隐窝基柱状（CBC）细胞和静止的“+4”细胞。在这里，我们将转录组学与蛋白质组学相结合，为 Lgr5(+)CBC 细胞定义明确的分子特征。使用两个微阵列平台对 FACS 分选的 Lgr5(+)干细胞及其后代进行转录谱分析，揭示了 384 个独特基因的 mRNA 干细胞特征。对同一细胞群进行定量质谱分析，鉴定出 278 种在肠干细胞中富集的蛋白质。mRNA 和蛋白质数据集显示出高度相关性，并定义了一个由 510 个富含干细胞的基因组成的组合特征。通过 mRNA 原位杂交进一步对空间表达模式进行了表征，结果表明，大约一半的基因呈梯度表达，在隐窝底部表达水平最高，而另一半则在 Lgr5(+)干细胞中特异性表达。使用新建立的一种签名基因 Smoc2 的敲入小鼠进行谱系追踪，证实了其干细胞特异性。利用这一资源，我们发现并通过独立方法证实，所提出的静止/“+4”干细胞标记物 Bmi1、Tert、Hopx 和 Lrig1 在 CBC 细胞中得到了稳健表达。
