HUMAN COLON STEM CELL AND CRYPT DYNAMICS

描述（申请人提供）： 目前对人类隐窝干细胞知之甚少。虽然创造了 可见的隐窝标记对人类来说是不切实际的， 来分析内在地记录隐窝历史的内源性序列。到 更好地区分其他相同的隐窝，而无需实验 干预后，表观遗传模式被用作细胞命运标记。甲基化 表现出体细胞遗传和随机位点独立变化， 潜在地在相邻的CpG位点中产生二进制信息串或标签 随时间漂移代替目视检查，甲基化标签内容 对单个隐窝进行取样并用亚硫酸氢盐测序进行读取。个标签 3个中性位点在腺窝和细胞间存在差异 在地窖里。甲基化随着年龄的增长而增加，但在隐窝之间呈镶嵌状， 以及单个隐窝内的等位基因和基因座之间的差异。有些地窖 准克隆，因为它们含有比预期的更多的独特标签。 单个干细胞用聚结分析复杂的表观遗传模式 理论更符合隐窝龛，其中多个干细胞是 通过周期性的对称分裂取代。甲基化标记显示正常 人类隐窝寿命长，含有多种干细胞，经历连续的 纯化，并在一些基因座积累随机甲基化错误。提出 研究将进一步验证甲基化标签作为细胞命运标记， 表征正常人结肠中的干细胞动力学。

DESCRIPTION (Provided by Applicant): Little is known about human crypt stem cells. Although strategies which create and follow visible crypt markers are impractical for humans, it may be possible to analyze endogenous sequences which inherently record crypt histories. To better distinguish between otherwise identical crypts without experimental intervention, epigenetic patterns were used as cell fate markers. Methylation exhibits somatic inheritance and random site independent changes which potentially create binary information strings or tags in adjacent CpG sites that drift with time. Instead of visual examinations, methylation tag contents of individual crypts are sampled and read with bisulfite sequencing. Tags at three presumably neutral loci were different between crypts and between cells within crypts. Methylation increased with aging but was mosaic between crypts, and between alleles and loci within single crypts. Some crypts were quasi‑clonal because they contained more unique tags than expected from a single stem cell. The complex epigenetic patterns analyzed with coalescence theory were more consistent with crypt niches in which multiple stem cells are replaced through periodic symmetric divisions. Methylation tags suggest normal human crypts are long lived, contain multiple stem cells, undergo continuous purification, and accumulate random methylation errors at some loci. Proposed studies will further verify methylation tags as cell fate markers and better characterize stem cell dynamics in normal human colon.