High incidence of non-random template strand segregation and asymmetric fate determination in dividing stem cells and their progeny.
High incidence of non-random template strand segregation and asymmetric fate determination in dividing stem cells and their progeny.
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DOI：
10.1371/journal.pbio.0050102
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发表时间：
2007-05
期刊：
影响因子：
9.8
通讯作者：
Rando TA
中科院分区：
文献类型：
--
作者：
Conboy MJ;Karasov AO;Rando TA
几十年前，“永生链假说”被提出，作为一种手段，干细胞可以限制获得可能导致癌症的突变，同时在生物体的生命周期中继续增殖。这一假设最初基于对胚胎细胞的观察，后来在干细胞自我更新方面进行了研究，但由于很少有额外的报告、显示模板链分离的细胞的稀有性以及涉及单一标签或遵循模板链的不同类型标签的实验的替代解释，这一假设在很大程度上仍未被接受。使用卤化胸苷类似物（溴脱氧尿苷 [BrdU]、氯脱氧尿苷 [CldU] 和碘脱氧尿苷 [IdU]）的连续脉冲，并分析体内诱导再生过程中的干细胞后代，我们观察到在细胞增殖扩张期间，较老和较年轻模板链的分离频率极高。 肌肉干细胞。此外，模板链共分离与不对称细胞分裂密切相关，产生具有不同命运的子代。继承旧模板的子细胞保留了更不成熟的表型，而继承新模板的子细胞获得了更加分化的表型。这些数据提供了基于模板年龄和与细胞命运决定相关的模板链共分离的令人信服的证据，表明在干细胞谱系进展过程中监测模板链年龄，并为解释标记保留细胞提出了重要的警告。对于每条染色体，互补的 DNA 链由最近一轮 DNA 复制期间合成的“年轻”链和上一次细胞分裂期间合成的“较老”链组成。当这些链在下一轮复制期间分离作为 DNA 合成的模板时，形成的两个姐妹染色单体因此在模板链年龄方面有所不同。 “永生链假说”预测，干细胞能够根据模板年龄区分染色单体：当它分裂时，自我更新的女儿将继承具有较旧模板的染色单体，而注定要分化的女儿将继承具有较新模板的染色单体。然而，支持这一假设的体内证据很少。通过在肌肉再生过程中干细胞/祖细胞的连续分裂中标记新合成的 DNA，我们观察到几乎一半的分裂细胞根据模板年龄对它们的染色单体进行排序。更加茎状的子代遗传了具有较旧模板的染色单体，而分化程度较高的子代遗传了具有较年轻模板的染色单体。我们认为这种现象是不对称分裂干细胞及其后代的一个特征。对增殖肌肉干细胞中较老和较年轻 DNA 模板链分离的分析提供了基于模板年龄并与细胞命运决定相关的共分离的令人信服的证据。
Decades ago, the “immortal strand hypothesis” was proposed as a means by which stem cells might limit acquiring mutations that could give rise to cancer, while continuing to proliferate for the life of an organism. Originally based on observations in embryonic cells, and later studied in terms of stem cell self-renewal, this hypothesis has remained largely unaccepted because of few additional reports, the rarity of the cells displaying template strand segregation, and alternative interpretations of experiments involving single labels or different types of labels to follow template strands. Using sequential pulses of halogenated thymidine analogs (bromodeoxyuridine [BrdU], chlorodeoxyuridine [CldU], and iododeoxyuridine [IdU]), and analyzing stem cell progeny during induced regeneration in vivo, we observed extraordinarily high frequencies of segregation of older and younger template strands during a period of proliferative expansion of muscle stem cells. Furthermore, template strand co-segregation was strongly associated with asymmetric cell divisions yielding daughters with divergent fates. Daughter cells inheriting the older templates retained the more immature phenotype, whereas daughters inheriting the newer templates acquired a more differentiated phenotype. These data provide compelling evidence of template strand co-segregation based on template age and associated with cell fate determination, suggest that template strand age is monitored during stem cell lineage progression, and raise important caveats for the interpretation of label-retaining cells. For each chromosome, the complementary DNA strands consist of a “younger” strand synthesized during the most recent round of DNA replication and an “older” strand synthesized during a previous cell division. When the strands separate to serve as templates for DNA synthesis during a subsequent round of replication, the two sister chromatids formed thus differ in terms of the template strand age. The “immortal strand hypothesis” predicts that a stem cell is capable of distinguishing between chromatids based on template age: when it divides, the self-renewing daughter will inherit the chromatids with the older templates, whereas the daughter destined to differentiate will inherit those with the newer templates. However, in vivo evidence in support of this hypothesis has been sparse. By labeling newly synthesized DNA in sequential divisions of stem/progenitors during muscle regeneration, we observed that almost half of the dividing cells sorted their chromatids based on template age. The more stem-like daughter inherited chromatids with older templates, and the more differentiated daughter inherited chromatids with younger templates. We propose that this phenomenon is a characteristic of asymmetrically dividing stem cells and their progeny. Analysis of the segregation of older and younger DNA template strands in proliferating muscle stem cells provides compelling evidence of co-segregation based on template age and associated with cell fate determination.
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影响因子：
4
作者：
Epting, CL;López, JE;Bernstein, HS
通讯作者：
Bernstein, HS
影响因子：
64.5
作者：
Sherwood, RI;Christensen, JL;Wagers, AJ
通讯作者：
Wagers, AJ
影响因子：
11.8
作者：
Conboy, IM;Rando, TA
通讯作者：
Rando, TA
影响因子：
21.3
作者：
Shinin, Vasily;Gayraud-Morel, Barbara;Tajbakhsh, Shahragim
通讯作者：
Tajbakhsh, Shahragim
DOI：
10.1111/j.1087-0024.2004.09305.x
发表时间：
2004-09-01
影响因子：
--
作者：
Potten, CS
通讯作者：
Potten, CS