位置的保存和鼠标Xist的独特表达来自非活性X染色体的Xist
N Brockdorff1, A Ashworth, G F Kay
1Section of Comparative Biology, MRC Clinical Research Centre, Harrow, UK.
Nature
|May 23, 1991
概括
哺乳动物X染色体不活化,确保基因剂量补偿的过程,涉及到特定的基因区域. 像人类XIST一样,小鼠Xist基因完全来自不活跃的X染色体,支持它在这个关键的调节现象中的作用.
科学领域:
- 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.
- 哺乳动物生物学 哺乳动物生物学
背景情况:
- X染色体不活化是雌性哺乳动物对基因剂量补偿的关键调节过程.
- 这种失活是由一个特定的区域控制的,即X失活中心 (XIC/Xic).
- 人类XIST基因位于XIC区域,仅从不活跃的X染色体表达出来.
研究的目的:
- 为了研究小鼠Xist基因的位置和表达模式.
- 为了确定小鼠XIST基因对人类XIST的同类是否在X染色体失活中起作用.
- 为了比较人类和小鼠之间的XIC/Xic区域和XIST/Xist基因功能.
主要方法:
- 在小鼠中Xic区域的比较映射.
- 在一种跨物种杂交小鼠模型 (Mus spretus/Mus musculus domesticus F1) 中分析Xist基因表达.
- 使用转位T(X;16) 16H来区分活跃和非活跃的X染色体.
主要成果:
- 小鼠Xist基因被映射到小鼠X染色体的Xic区域.
- 发现Xist在混合小鼠模型中仅从非活性X染色体表达.
- 人类XIST和小鼠Xist之间保留了染色体合成和专属不活跃X表达.
结论:
- 小鼠Xist基因位于Xic区域,类似于人类的XIC.
- 从非活跃的X染色体中Xist的独家表达支持其在X染色体失活中的作用.
- 染色体位置和表达模式的保存表明哺乳动物中X染色体不活化的共享机制.
相关概念视频
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.
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...
Euchromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions take up more dye, appearing darker, while the less-compact areas take up less dye and appear lighter. Based on the compaction level, chromatins are classified into two primary forms – euchromatin and heterochromatin.
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
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...
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.
Heterochromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions that take up more dye are called heterochromatin. Heterochromatin is further classified into two forms – constitutive heterochromatin and facultative heterochromatin.
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...


