酵母菌におけるヌクレオソーム依存遺伝子発現と静止の染色体景観
J J Wyrick1, F C Holstege, E G Jennings
1Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA.
Nature
|December 10, 1999
まとめ
ヒストンは,特に酵母細胞のテロメアにおいて,Sir-独立の方法で,遺伝子の静止に寄与する. 核粒子の枯渇は,遺伝子発現に世界的な影響を及ぼし,テロメア-近接遺伝子に特定の影響を及ぼします.
科学分野:
- 分子生物学は分子生物学である.
- 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
背景:
- ユカリオットのゲノムは核細胞に編成され,それらは一般的に遺伝子発現を抑制する.
- 酵母菌のテロメア型ヘテロクロマチンは,静音情報調節器 (SIR) 複合体とRap1.1によって媒介される遺伝子サイレンシングを示す.
- 全球的な遺伝子調節における核細胞と静止因子の正確な役割は,依然として調査の分野です.
研究 の 目的:
- 酵母菌におけるグローバルな遺伝子発現に対する核細胞と静止因子の影響を調査する.
- テロメア静音化にヒストンの寄与を決定する.
- ヒストンの遺伝子特異的対一般的抑圧的役割を明らかにする.
主な方法:
- 酵母における高密度配列を用いて,遺伝子発現を研究した.
- 枯渇した核体ヒストン,特にヒストンH4.
- 静音因子の枯渇による影響を評価した.
主要な成果:
- ヒストンH4レベルを低下させると,酵母遺伝子の25%の発現が変化した (15%増加,10%減少).
- テロメア近接遺伝子は,テロメアから最大20キロベースまでの抑制を解除し,既知のSirタンパク質結合範囲を超えました.
- ヒストンの枯渇は,酵母遺伝子の過半数 (75%) の発現に最小限の影響を及ぼしました.
結論:
- ヒストンは,SIR複合体とは独立してテロメア静音化に重要な役割を果たします.
- 核細胞は,既定の静止因子結合部位を超えたテロメアでの遺伝子抑制に寄与する.
- 遺伝子調節におけるヒストンの機能は文脈に依存しており,テロメア領域の外で遺伝子特異的な役割を果たしている.
関連する概念動画
Position-effect Variegation
In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
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...
Chromatin Position Affects Gene Expression
Chromatin is the massive complex of DNA and proteins packaged inside the nucleus. The complexity of chromatin folding and how it is packaged inside the nucleus greatly influences access to genetic information. Generally, the nucleus' periphery is considered transcriptionally repressive, while the cell's interior is considered a transcriptionally active area.
Topologically Associated Domains (TADs)
The 3-dimensional positioning of chromatin in the nucleus influences the timing and level of...
Topologically Associated Domains (TADs)
The 3-dimensional positioning of chromatin in the nucleus influences the timing and level of...
Eukaryotic Transcription Inhibitors
Certain biochemical processes, such as embryonic development and cell growth regulation, depend on the repression of specific genes. DNA binding proteins known as eukaryotic transcription inhibitors regulate the repression of gene expression in eukaryotes. The presence of these inhibitors at the required location and time in the cell is triggered by the presence of hormones and additional signals from other cells.
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
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...
Epigenetic Regulation
Epigenetic changes alter the physical structure of the DNA without changing the genetic sequence and often regulate whether genes are turned on or off. This regulation ensures that each cell produces only proteins necessary for its function. For example, proteins that promote bone growth are not produced in muscle cells. Epigenetic mechanisms play an essential role in healthy development. Conversely, precisely regulated epigenetic mechanisms are disrupted in diseases like cancer.
X-chromosome...
X-chromosome...


