从活跃的X染色体中阻碍Xist表达改善了小鼠体细胞核转移
Kimiko Inoue1, Takashi Kohda, Michihiko Sugimoto
1BioResource Center, RIKEN, 305-0024 Tsukuba, Japan.
概括
科学家通过识别和纠正特定的基因组重编程错误来改进哺乳动物克隆. 在克隆胚胎中删除Xist基因显著提高了克隆效率,并纠正了基因表达问题.
科学领域:
- 生殖生物学 生殖生物学
- 遗传学 是一个遗传学.
- 表观遗传学 在表观遗传学中,表观遗传学是指表观遗传学.
背景情况:
- 体细胞核转移 (SCNT) 是克隆哺乳动物的一个关键技术.
- 由于捐赠细胞基因组的不完全重编程,SCNT的效率较低.
- 在SCNT重编程中的特定,非随机错误尚未得到充分理解.
研究的目的:
- 为了调查非随机的,SCNT特定的重编程错误.
- 确定导致这些错误的机制,并探索提高克隆效率的策略.
主要方法:
- 通过SCNT生成的克隆小鼠胚胎的分析.
- 研究了Xist的表达,这是一种参与X染色体失活的非编码RNA.
- 从活跃的X染色体 (Xa) 中利用Xist的遗传删除.
- 在克隆胚胎中评估了全球基因表达和基因组修饰.
主要成果:
- 从活跃的X染色体 (Xa) 获得Xist的异胎表达,在两性克隆小鼠胚胎中观察到.
- 在克隆胚胎中从Xa中删除Xist导致了正常的全球基因表达.
- 删除Xist导致克隆效率提高了8到9倍.
- 发现了一种Xist独立的机制,涉及压制性基因素标记,可以降低特定的X链接基因的调节.
结论:
- 鉴定出异位Xist表达和Xist独立的质子修饰作为SCNT中的非随机重编程错误.
- 证明纠正这些错误,特别是从Xa中删除Xist,可以显著提高克隆效率.
- 这些发现为改善哺乳动物克隆的SCNT方法提供了途径.
相关概念视频
Inheritance of Chromatin Structures
Epigenetics is the study of inherited changes in a cell's phenotype without changing the DNA sequences. It provides a form of memory for the differential gene expression pattern to maintain cell lineage, position-effect variegation, dosage compensation, and maintenance of chromatin structures such as telomeres and centromeres. For example, the structure and location of the centromere on chromosomes are epigenetically inherited. Its functionality is not dictated or ensured by the underlying DNA...
X-Inactivation
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results.
X-inactivation
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results.
Methods of Nuclear Reprogramming
Nuclear reprogramming is a process of transforming one cell type into an unrelated cell type by epigenetic changes that alter the cell’s original gene expression pattern. Such epigenetic changes force cells to express a different set of genes, which play a significant role in inducing transformation into other cell types. Nuclear reprogramming offers applications in reproductive cloning for livestock propagation and regenerative medicine — developing patient-specific cells for injury repair.
Dosage Compensation
In animals, gender is determined by the number and type of sex chromosome. For example, human females have two X chromosomes, and males have one X and one Y chromosome, whereas C.elegans with one X chromosome is a male, and the one with two X chromosomes is a hermaphrodite.
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...
In-vitro Mutagenesis
To learn more about the function of a gene, researchers can observe what happens when the gene is inactivated or “knocked out,” by creating genetically engineered knockout animals. Knockout mice have been particularly useful as models for human diseases such as cancer, Parkinson’s disease, and diabetes.


