Self-Correction of Chromosomal Abnormalities in Human Preimplantation Embryos and Embryonic Stem Cells
Self-Correction of Chromosomal Abnormalities in Human Preimplantation Embryos and Embryonic Stem Cells
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DOI：
10.1089/scd.2013.0053
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发表时间：
2013-09-01
影响因子：
4
通讯作者：
Baharvand, Hossein
中科院分区：
文献类型：
--
作者：
Bazrgar, Masood;Gourabi, Hamid;Baharvand, Hossein
非整倍体常见于人类植入前胚胎中，尤其是在卵裂阶段，因为第三次细胞分裂导致基因组激活。非整倍体胚胎已用于衍生正常胚胎干细胞（ESC）系和发育模型。这篇综述讨论了人类植入前胚胎和人类胚胎干细胞中的非整倍性以及这些畸变自我纠正的潜力。二倍体-非整倍体嵌合体是最常见的异常现象。因此，在卵裂期或囊胚期通过植入前遗传学诊断选择的胚胎可能存在部分异常。分化被认为是通过异常细胞的死亡和/或分裂减少来消除嵌合胚胎的障碍。然而，一些镶嵌现象，例如拷贝数变异，可能与活产兼容。人们提出了在发育后期对非整倍体进行自我校正的几个原因，包括原发性误诊、滋养外胚层中非整倍体的分配、嵌合胚胎中二倍体细胞的细胞生长优势、非整倍体细胞分裂的滞后、非整倍体染色体的挤出或重复以及DNA修复基因产物的丰度。尽管需要更多的研究来理解自我纠正这种罕见现象的机制，但它很可能与克服镶嵌现象有关。
Aneuploidy is commonly seen in human preimplantation embryos, most particularly at the cleavage stage because of genome activation by third cell division. Aneuploid embryos have been used for the derivation of normal embryonic stem cell (ESC) lines and developmental modeling. This review addresses aneuploidies in human preimplantation embryos and human ESCs and the potential of self-correction of these aberrations. Diploid-aneuploid mosaicism is the most frequent abnormality observed; hence, embryos selected by preimplantation genetic diagnosis at the cleavage or blastocyst stage could be partly abnormal. Differentiation is known as the barrier for eliminating mosaic embryos by death and/or decreased division of abnormal cells. However, some mosaicisms, such as copy number variations could be compatible with live birth. Several reasons have been proposed for self-correction of aneuploidies during later stages of development, including primary misdiagnosis, allocation of the aneuploidy in the trophectoderm, cell growth advantage of diploid cells in mosaic embryos, lagging of aneuploid cell division, extrusion or duplication of an aneuploid chromosome, and the abundance of DNA repair gene products. Although more studies are needed to understand the mechanisms of self-correction as a rare phenomenon, most likely, it is related to overcoming mosaicism.