位置の保存とマウスXISTの排他的発現は,不活性X染色体から発生する
N Brockdorff1, A Ashworth, G F Kay
1Section of Comparative Biology, MRC Clinical Research Centre, Harrow, UK.
Nature
|May 23, 1991
まとめ
哺乳類のX染色体不活性化は,遺伝子用量補償を保証するプロセスであり,特定の遺伝子領域が関与しています. マウスXIST遺伝子は,ヒトXISTと同じく,非活性X染色体から独占的に発現し,この重要な規制現象におけるX染色体の役割をサポートしています.
科学分野:
- 遺伝学 遺伝学とは
- エピジェネティクス エピジェネティクス
- 哺乳類生物学 哺乳類生物学について
背景:
- X染色体不活性化は,雌性哺乳類における遺伝子用量補償の重要な規制プロセスである.
- この不活性化は,特定の領域であるX不活性化センター (XIC/Xic) によって制御されます.
- XIC領域に位置するヒトのXIST遺伝子は,不活性X染色体からのみ発現する.
研究 の 目的:
- マウスXist遺伝子の位置と発現パターンを調査する.
- ヒトのXISTと同型であるマウスXIST遺伝子がX染色体不活性化に作用するかどうかを判断する.
- 人間とマウスのXIC/Xic領域とXIST/Xist遺伝子の機能を比較する.
主な方法:
- マウスのXic領域の比較マッピング.
- 異種間ハイブリッドマウスモデル (Mus spretus/Mus musculus domesticus F1) でのXist遺伝子発現の分析
- トランスロケーションT ((X;16) 16Hを用いて,活性X染色体と非活性X染色体を区別する.
主要な成果:
- マウスXist遺伝子はマウスX染色体のXic領域にマッピングされました.
- Xistは,ハイブリッドマウスモデルにおける不活性X染色体からのみ発現することが判明しました.
- 人間のXISTとマウスのXistの間に染色体合成と独占的な非活性X発現が保存された.
結論:
- マウスのXist遺伝子はXic領域に位置し,人間のXICに類似しています.
- 不活性X染色体からのXistの排他的発現は,X染色体不活性化におけるXistの役割を支持する.
- 染色体の位置と発現パターンの保存は,哺乳類におけるX染色体不活性化の共通のメカニズムを示唆しています.
関連する概念動画
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...


