通过人类DNA聚合酶-eta的低保真度DNA合成
T Matsuda1, K Bebenek, C Masutani
1Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
Nature
|May 9, 2000
概括
人类DNA聚合酶eta (pol-eta),以前认为没有错误,在复制未受损的DNA时表现出低保真度. 这种DNA聚合酶缺乏校对,导致严重的基替代错误,并表明其功能需要严格控制.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 生物化学 生物化学
背景情况:
- DNA聚合酶对于DNA复制和修复至关重要.
- 损伤旁路DNA聚合酶是参与DNA损伤耐受性的专门家族.
- 人类DNA聚合酶eta (pol-eta) 是由XPV基因编码的,与皮肤癌易感性有关.
研究的目的:
- 为了研究人类DNA聚合酶eta (pol-eta) 在未受损DNA复制过程中的忠实性.
- 为了确定pol-eta之前描述的"无错误"绕过丁氨酸-丁氨酸二次数是否准确地反映了其整体保真度.
主要方法:
- 在体外合成测试中使用纯化的人类聚乙烯.
- 对未受损坏的DNA模板上的基替代错误率的分析.
- 在pol-eta.的内在校对外核酶活动的评估.
主要成果:
- 与其他依赖模板的DNA聚合酶相比,人类的pol-eta对未受损DNA的忠实度明显较低.
- 聚乙烯缺乏内在的校对外核酶活性.
- 错误率的范围从每18个基替换一次到380个合成的核酸,这取决于不匹配.
结论:
- 人类的pol-eta并非没有错误,并且以非常低的保真度合成未受损的DNA.
- 放松的基配对要求表明,pol-eta的功能可能受到严格调节,以防止突变性合成.
- 这些发现挑战了"无错误"的称号,并突出了不受控制的pol-eta活动的潜在风险.
相关概念视频
Replication in Eukaryotes
Overview
Proofreading
Synthesis of new DNA molecules starts when DNA polymerase links nucleotides together in a sequence that is complementary to the template DNA strand. DNA polymerase has a higher affinity for the correct base to ensure fidelity in DNA replication. The DNA polymerase furthermore proofreads during replication, using an exonuclease domain that cuts off incorrect nucleotides from the nascent DNA strand.Errors during Replication Are Corrected by the DNA Polymerase EnzymeGenomic DNA is synthesized in...
DNA Replication
DNA replication involves the separation of the two strands of the double helix, with each strand serving as a template from which the new complementary strand is copied. After replication, each double-stranded DNA includes one parental or “old” strand and one “new” strand. This is known as semiconservative replication. The resulting DNA molecules have the same sequence and are divided equally into the two daughter cells.
Replication in Prokaryotes
DNA replication uses a large number of...
Replication in Prokaryotes
DNA replication uses a large number of...
Translesion DNA Polymerases
Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
Proofreading
Synthesis of new DNA molecules is carried out by the enzyme DNA polymerase, which adds nucleotides on the daughter strand complementary to the template DNA strand. DNA polymerase has a higher affinity to add the correct base and ensures fidelity during DNA replication. Furthermore, it exhibits proofreading activity during replication, using an exonuclease domain that cuts off incorrect nucleotides from the nascent DNA strand.
Errors During Replication are Corrected by the DNA Polymerase Enzyme
Errors During Replication are Corrected by the DNA Polymerase Enzyme
Replication in Eukaryotes
In eukaryotic cells, DNA replication is highly conserved and tightly regulated. Multiple linear chromosomes must be duplicated with high fidelity before cell division, so there are many proteins that fulfill specialized roles in the replication process. Replication occurs in three phases: initiation, elongation, and termination, and ends with two complete sets of chromosomes in the nucleus.
Many Proteins Orchestrate Replication at the Origin
Eukaryotic replication follows many of the same...
Many Proteins Orchestrate Replication at the Origin
Eukaryotic replication follows many of the same...


