单链hTERT促进体片段中的三级DNA结构通过协作或顺序事件通过并行路径展开和重新折叠
Zhongbo Yu1, Vanessa Gaerig, Yunxi Cui
1Department of Chemistry and Biochemistry and School of Biomedical Sciences, Kent State University, Kent, Ohio 44242, United States.
Journal of the American Chemical Society
|March 1, 2012
概括
研究人员发现了DNA发针和G-四重复结构之间的三级相互作用. 在人类端粒酶促进体DNA中的这一发现揭示了复杂的折叠机制和生物功能.
科学领域:
- 分子生物学分子生物学
- 生物物理学的生物物理.
- 遗传学 是一个遗传学.
背景情况:
- 在双螺旋之外,DNA表现出结构多样性,包括G-四重复和发针.
- 多个DNA二次结构之间的三级相互作用的潜力在很大程度上仍未被探索.
- 了解DNA复杂结构对于破译基因调节和细胞功能至关重要.
研究的目的:
- 为了研究含有头和G-四重复结构的单链DNA内部的三级相互作用.
- 为更高阶DNA复合体形成提供动力学和热力学证据.
- 阐明特定的DNA二次结构在调解这些相互作用中的作用.
主要方法:
- 利用激光刀仪器,获得机械展开和重新折叠的DNA痕迹.
- 开发了一种新的数据分析策略,利用展开和重新折叠之间的歇斯底里区域.
- 采用位点定向的突变发生和补充DNA片段的添加来破坏发针形成.
主要成果:
- 介绍了第一个令人信服的动力学和热力学证据,证明了人类端粒酶促进体DNA中针头和G-四重体之间的三级相互作用.
- 在层次的展开和重新折叠过程中,确定了一个15核酸针作为一种常见的中间物种.
- 证明扰乱针头形成消除了合作动态事件,证实了针头在调解三级相互作用中的作用.
结论:
- 这些发现直接证实了DNA复合体重新折叠中的统一动态分区机制,此前仅在蛋白质和RNA中观察到.
- 这项研究合理化了关于复杂单链DNA中长距离相互作用的有争议的观察结果.
- 在促进子元素中发现的复杂性突出显示了复杂的DNA结构在细胞过程中的功能意义.
相关概念视频
01:53Bacterial Transcription
RNA polymerase (RNAP) carries out DNA-dependent RNA synthesis in both bacteria and eukaryotes. Bacteria do not have a membrane-bound nucleus. So, transcription and translation occur simultaneously, on the same DNA template.
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
01:19RNA Structure
The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form complex secondary and tertiary structures. Such structures play essential roles in the regulation of transcription and translation.
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA) involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three...
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA) involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three...
01:23RNA Structure
Overview
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form complex secondary and tertiary structures. Such structures play essential roles in the regulation of transcription and translation.
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA): messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three RNA types consist of a...
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form complex secondary and tertiary structures. Such structures play essential roles in the regulation of transcription and translation.
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA): messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three RNA types consist of a...
02:31Homologous Recombination
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...
03:01The Replisome
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
02:13Cooperative Binding of Transcription Regulators
Transcriptional regulators bind to specific cis-regulatory sequences in the DNA to regulate gene transcription. These cis-regulatory sequences are very short, usually less than ten nucleotide pairs in length. The short length means that there is a high probability of the exact same sequence randomly occurring throughout the genome. Since regulators can also bind to groups of similar sequences, this further increases the chances of random binding. Transcriptional regulators form dimers that...