Skewed X chromosome inactivation in diploid and triploid female human embryonic stem cells
Skewed X chromosome inactivation in diploid and triploid female human embryonic stem cells
复制标题
二倍体和三倍体女性人类胚胎干细胞中 X 染色体倾斜失活
DOI：
10.1093/humrep/dep126
复制
发表时间：
2009-08-01
影响因子：
6.1
通讯作者：
Sun, Xiaofang
中科院分区：
文献类型：
--
作者：
Liu, Weiqiang;Sun, Xiaofang
人胚胎干细胞是研究表观遗传机制的重要模型。hESC的表观遗传稳定性对于确保这些细胞在再生医学中的质量和安全性至关重要。X染色体失活（XCI）是最早可测量的表观遗传现象之一，本实验室建立了5个二倍体（包括1个易位系）和1个三倍体人胚胎干细胞系，通过甲基化特异性PCR方法分析了人雄激素受体（HUMARA）基因的XCI状态。对于XCI偏斜，仅进一步分析了具有HUMARA杂合基因座的hESC系，无论其核型如何，所有检测的hESC系在非常早的传代的未分化阶段都具有活性和失活的X染色体。一个线表现出随机的XCI状态，虽然其余四个杂合线表现出一个非常歪斜的XCI模式。这种偏斜的XCI模式在分化前保持稳定。另外，在长期培养后，具有两条活性X染色体的三倍体hESC系的XCI模式发生了变化，在本研究所用的雌性hESC中发现了两种类型的XCI模式。大多数hESC属于XCI模式极度偏斜的一类，尽管另一类包括具有随机XCI的hESC。三倍体hESC系的XCI模式逐渐变化，并最终在长期培养后达到极偏斜的XCI模式。我们的研究表明，在hESC细胞系之间，甚至在同一细胞系的不同传代中，X失活存在很大的变异性。
Human embryonic stem cells (hESCs) are interesting models for the study of epigenetic mechanisms. Epigenetic stability in hESCs is critical to ensure the quality and safety of these cells in regenerative medicine. One of the first measurable epigenetic phenomena is X chromosome inactivation (XCI).XCI status was analyzed by methylation-specific PCR of the human androgen receptor (HUMARA) gene in five diploid (including one translocation line) and one triploid hESC lines established in our laboratory. For XCI skewing, only the hESC lines with a HUMARA heterozygous locus were further analyzed.Irrespective of their karyotypes, all hESC lines examined had active and inactive X chromosomes in the undifferentiated stage at very early passages. One line exhibited a random XCI status, although the remaining four heterozygous lines showed an extremely skewed XCI pattern. This skewed XCI pattern remained stable until differentiation. In addition, the XCI pattern in a triploid hESC line with two active X chromosomes varied after long-term culture.Two types of XCI pattern were found in the female hESCs used in this study. Most hESCs fell into one category where the XCI pattern is extremely skewed, although the other category includes hESCs with random XCI. The XCI pattern in a triploid hESC line varies gradually and eventually reaches an extremely skewed XCI pattern after long-term culture. Our study demonstrates that there is a large variability in terms of X inactivation among hESC lines, and even at different passages of the same line.