在CRISPR-Cas适应过程中,Cas9指定了功能性病毒标
Robert Heler1, Poulami Samai1, Joshua W Modell1
1Laboratory of Bacteriology, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA.
Nature
|February 25, 2015
概括
Cas9蛋白在间隔器获取过程中识别特定的DNA序列,称为PAMs,这对细菌的适应性免疫至关重要. 这一发现揭示了Cas9在培养 prokaryotic 免疫记忆中的新角色.
科学领域:
- 微生物学 微生物学
- 分子生物学分子生物学
- 免疫学 免疫学 免疫学
背景情况:
- Prokaryotes 通过 CRISPR-Cas 系统对病毒具有适应性免疫力.
- 克里斯普尔-卡斯系统使用小RNA分子引导卡斯核酶向病毒DNA.
- 链球菌 (Streptococcus pyogenes Cas9) 需要一个原体空间体相邻基因 (PAM) 来进行DNA裂变.
研究的目的:
- 研究CRISPR-Cas系统中间隔器获取的机制.
- 为了确定Cas9是否在获取过程中在选择间隔序列中发挥作用.
- 阐明 PAM 识别在 prokaryotic 免疫记忆生成中的作用.
主要方法:
- 对Cas9等位基因的基因操纵,以改变PAM识别.
- 在Streptococcus pyogenes中对间隔器获取特异性的分析.
- 同免疫沉试验用于研究获取机制中的蛋白质相互作用.
主要成果:
- 在间隔器获取过程中,Cas9直接识别PAM序列.
- 修改或删除Cas9修改间隔器获取特异性的PAM识别图案.
- Cas9与其他获取蛋白 (Cas1,Cas2,Csn2) 相互作用,从而赋予PAM特异性.
结论:
- 在获得新的间隔器时,Cas9在识别PAM序列方面具有新功能.
- 这种由Cas9识别的PAM对于 prokaryotic适应性免疫的特异性至关重要.
- 这项研究建立了一种新的机制,用于在核细胞中产生免疫记忆.
相关概念视频
01:59CRISPR
60.3K
Genome editing technologies allow scientists to modify an organism’s DNA via the addition, removal, or rearrangement of genetic material at specific genomic locations. These types of techniques could potentially be used to cure genetic disorders such as hemophilia and sickle cell anemia. One popular and widely used DNA-editing research tool that could lead to safe and effective cures for genetic disorders is the CRISPR-Cas9 system. CRISPR-Cas9 stands for Clustered Regularly Interspaced...
60.3K
01:59CRISPR
19.0K
19.0K
01:28CRISPR/Cas9 Genome Editing
3.2K
The CRISPR-Cas system serves as a bacterial defense mechanism against invading genetic elements such as viruses and plasmids, forming the foundation for its adaptation as a powerful genome-editing tool. Originally discovered in prokaryotes, this system has been repurposed to revolutionize genetic engineering across a wide range of organisms, including plants, animals, and humans. The core component, Cas9, is an endonuclease derived from Streptococcus pyogenes, capable of introducing...
3.2K
02:53CRISPR and crRNAs
20.4K
Bacteria and archaea are susceptible to viral infections just like eukaryotes; therefore, they have developed a unique adaptive immune system to protect themselves. Clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins (CRISPR-Cas) are present in more than 45% of known bacteria and 90% of known archaea.
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
20.4K
01:23The Antiviral System of Bacteria and Archaea: CRISPR
1.0K
CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats is a adaptive immune system found in bacteria and archaea that protects against viral infections. This system enables prokaryotic cells to identify, remember, and neutralize foreign genetic elements, primarily bacteriophages, by storing fragments of the invader’s DNA as a genetic memory.The CRISPR immune response begins during an initial infection. Cas (CRISPR-associated) proteins play a central role in this...
1.0K
02:31Homologous Recombination
65.9K
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...
65.9K