ドロソフィラ結末性硬化症複合体の遺伝子ホモログは,細胞成長と細胞増殖を制限する
1Massachusetts General Hospital Cancer Center, Charlestown, MA 02129, USA.
Cell
|May 12, 2001
まとめ
結核性硬化症は遺伝疾患で,TSC1またはTSC2の変異によって生じる. ドロソフィラのこれらの遺伝子を非活性化すると,同種のフェノタイプが生まれ,成長と細胞サイズが向上し,ヒトの疾患メカニズムに関する洞察が得られます.
科学分野:
- 遺伝学 遺伝学とは
- 発達生物学 発達生物学について
- 細胞生物学 細胞生物学
背景:
- 結核性硬化症はヒトの遺伝性疾患で,ハマルトマト性腫瘍が特徴です.
- TSC1またはTSC2遺伝子の変異は,結核性硬化症の既知の原因である.
- TSC1およびTSC2タンパク質は,細胞の成長と増殖を調節する複合体を形成します.
研究 の 目的:
- ドロソフィラのTsc1およびTsc2/gigas遺伝子の機能を特徴付ける.
- 結核性硬化症の根底にある細胞メカニズムを調査する.
- TSCの病原性における細胞周期調節体の役割を調査する.
主な方法:
- ドロソフィラ Tsc1 と Tsc2/gigas の遺伝子に不活性化変異が導入されました.
- 変異性ドロソフィラのフェノタイプ分析を行い,成長と細胞サイズに焦点を当てました.
- 細胞サイクル進行とサイクリンレベルは,変異細胞で分析されました.
主要な成果:
- Tsc1またはTsc2/gigasの無活性化変異は,同一のフェノタイプをもたらしました:成長が強化され,プロイジーの変化なしに細胞サイズが増加しました.
- 変異細胞は,細胞周期のG1期に費やされる時間が短縮された.
- Tsc1とTsc2の共発は組織成長を制限し,細胞サイズを小さくし,細胞増殖を減少させた.
- サイクリンEとサイクリンAのレベルの上昇は,転移後の変異細胞で観察され,不適切な細胞サイクル再入力を示唆しました.
結論:
- ドロソフィラのTsc1およびTsc2/gigas遺伝子は,細胞の成長,サイズ,増殖を調節する上で重要な役割を果たします.
- Tsc1またはTsc2の機能の喪失は,ヒトの結核硬化症の側面を模倣する細胞サイクル不調につながる.
- サイクリンレベルは,Tsc1/Tsc2変異に関連するフェノタイプを調節する上で重要である.
関連する概念動画
01:23Negative Regulator Molecules
Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
02:34Inhibition of Cdk Activity
The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
02:15Replicative Cell Senescence
Replicative cell senescence is a property of cells that allows them to divide a finite number of times throughout the organism's lifespan while preventing excessive proliferation. Replicative senescence is associated with the gradual loss of the telomere — short, repetitive DNA sequences found at the end of the chromosomes. Telomeres are bound by a group of proteins to form a protective cap on the ends of chromosomes. Embryonic stem cells express telomerase — an enzyme that adds the telomeric...
02:23Abnormal Proliferation
Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
03:03mTOR Signaling and Cancer Progression
The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
The mTOR pathway or the...
01:05Cancer-Critical Genes II: Tumor Suppressor Genes
Genes usually encode proteins necessary for the proper functioning of a healthy cell. Mutations can often cause changes to the gene expression pattern, thereby altering the phenotype.
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...