环素A在线粒分裂对完成DNA复制的依赖性中的作用
1Howard Hughes Medical Institute, University of Colorado School of Medicine, Denver 80262.
Nature
|November 28, 1991
概括
环素A对于细胞周期的进展至关重要. 它的去除导致Xenopus蛋提取物中过早的线粒分裂和不完整的DNA合成,突出其重要的调节作用.
科学领域:
- 细胞生物学 细胞生物学
- 分子生物学分子生物学
- 发育生物学 发展生物学
背景情况:
- 环素调节细胞循环,A型和B型环素在较高的真核生物中起着关键作用.
- 环林A和B型环林具有不同的降解时间,这表明它们在细胞循环控制中发挥着独特的作用.
- 循环素降解对于退出线粒分裂至关重要.
研究的目的:
- 调查环林A在细胞周期进展中的特定作用.
- 了解Xenopus蛋提取物中循环蛋白A剥离的功能后果.
主要方法:
- 在Xenopus蛋提取物中使用反感性寡氧核酸来耗尽环素AmRNA.
- 研究了细胞循环的进展,包括DNA合成和线粒分裂的进入,在缺乏环林A的提取物中.
- 评估了添加回林A mRNA或蛋白质的影响.
主要成果:
- 除环林A导致了环林B-cdc2激酶的过早激活.
- 缺乏环素A的提取物在完成DNA复制 (S阶段) 之前,过早进入线粒分裂.
- 重新引入环林A恢复了正常细胞循环的进展.
结论:
- 环素A在调节线粒体进入的时间和确保适当完成S阶段方面发挥着至关重要的作用.
- 环素A作为一个独特的调节剂,与环素B分开,控制细胞循环的进展.
- 这些发现强调了精确的环素A功能对于精确的细胞分裂的重要性.
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...
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The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
Restriction Enzymes
Restriction enzymes are bacterial enzymes used to cut DNA in a sequence-specific manner. To cleave DNA, they bind to specific palindromic sequences called restriction sites. Such palindromic DNA sequences or inverted repeats are commonly found in regions of functional significance, such as the origin of replication, gene operator sites, and regions containing transcription termination signals.
The host bacteria protect their own genomic DNA from these enzymes by methylating these sites. Some...
The host bacteria protect their own genomic DNA from these enzymes by methylating these sites. Some...
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...


