不滅の糸? 不滅の糸? ちょっと休憩をさせて下さい.
1Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC, Canada. plansdor@bccrc.ca
Cell
|July 3, 2007
まとめ
幹細胞は,変異を避けるために"古い"DNAを保持しないかもしれません. 代わりに,姉妹染色体間の表遺伝的差異は,非対称な細胞分裂と細胞運命を導く可能性があります.
科学分野:
- 細胞生物学 細胞生物学
- 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:
- "不死の鎖"仮説は,幹細胞が"古い"DNAを保持し,突然変異の蓄積を防ぐことを示唆しています.
- この仮説は,非対称的に分裂する幹細胞における選択的染色体保持を前提としている.
研究 の 目的:
- "不滅の糸"仮説を評価するために.
- 非対称な細胞分裂と細胞運命を制御するための代替メカニズムを提案する.
主な方法:
- このエッセイでは,既存の仮説をレビューし,新しいモデルを提案します.
- 議論は,エピジェネティックコントロールと対照的にDNAベースの保持の生物学的妥当性に焦点を当てています.
主要な成果:
- 幹細胞が"古い"DNAを保持する"不死の鎖"仮説は,ありえないように思われる.
- 姉妹染色体間の表遺伝的差異は,幹細胞の分裂と運命についてより妥当な説明を提供します.
結論:
- 非対称な細胞分裂と幹細胞の運命は,おそらく"古い"DNAの選択的な保持ではなく,表遺伝的差異によって導かれる.
- このエピジェネティックモデルは,幹細胞の行動と突然変異の予防について,より控えめな説明を提供します.
関連する概念動画
Lagging Strand Synthesis
During replication, the complementary strands in double-stranded DNA are synthesized at different rates. Replication first begins on the leading strand. Replication starts later, occurs more slowly, and proceeds discontinuously on the lagging strand.
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
Fixing Double-strand Breaks
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
Replicative 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...
Lagging Strand Synthesis
During replication, the complementary strands in double-stranded DNA are synthesized at different rates. Replication first begins on the leading strand. Replication starts later, occurs more slowly, and proceeds discontinuously on the lagging strand.
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
Fixing Double-strand Breaks
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
Replicative 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...


