CRISPR/Cas系统是细菌体内的获得性免疫系统, 是用来对抗侵略细菌的外源DNA, 质粒和噬菌体的. 与普通的原核生物的general的免疫系统不一样, CRISPR/Cas系统是获得性免疫系统, 这就意味着这个免疫系统是具备“记忆性”的. 他可以记住入侵过的外源DNA 和噬菌体, 并在他们再次入侵的时候切断他们基因组, 被切断的基因组将变为线性,无法进行复制和表达,并被细菌体内的酶降解掉. 这个免疫系统虽说简单, 但是却非常实用且强大. CRISPR 系统是一个什么样的结构呢. 简而言之, …

Simplified diagram of a CRISPR locus. The three major components of a CRISPR locus are shown: cas genes, a leader sequence, and a repeat-spacer array. Repeats are shown as gray boxes and spacers are colored bars.

CRISPR（clustered regularly interspaced short palindromic repeats，成簇的规律间隔短回文重复序列）和CRISPR-associated protein 9（Cas9）共同组成的这套CRISPR-Cas9系统是一种细菌抵抗噬菌体DNA注入和质粒转移的天然防御机制。

The genetic information that produces a CRISPR-Cas system is found at a single genomic location or 'locus'. A CRISPR locus has two main parts: a cluster of genes encoding Cas proteins and the CRISPR array, which consists of between two and several hundred repeating sequences of DNA letters (each 25-35 letters long) separated by unique spacers ...

CRISPR-Cas comprises a genomic locus called CRISPR that harbours short repetitive elements (repeats) separated by unique sequences (spacers), which can originate from mobile genetic elements (MGEs) such as bacteriophages, transposons or plasmids.

Historical timeline of discoveries of the components of the CRISPR–Cas9 system. 1987 – Short DNA repeats, later called CRISPR, were first noticed in bacterial genomes, and, in 1995, also found in archaea. 2005 – The role of CRISPR loci in the protection of prokaryotes from foreign genetic information was proposed, and the Cas9 protein was ...

The action of the CRISPR-Cas system is usually divided into three stages: (1) adaptation or spacer integration, (2) processing of the primary transcript of the CRISPR locus (pre-crRNA) and maturation of the crRNA which includes the spacer and variable regions corresponding to 5′ and 3′ fragments of CRISPR repeats, and (3) DNA (or RNA ...

Bacteria and archaea possess adaptive immunity against foreign genetic elements using CRISPR–Cas systems. Upon infection, new foreign DNA sequences are captured and integrated into the host CRISPR locus as new spacers. The CRISPR locus is transcribed and processed to generate mature CRISPR RNAs, each encoding a unique spacer sequence.

2018年3月9日 · CRISPR-Cas systems provide bacteria and archaea with diverse mechanisms of adaptive immunity, illuminating the evolutionary pressures imposed by selfish genetic elements.

2017年7月20日 · CRISPR-Cas systems depend on the Cas1-Cas2 integrase to capture and integrate short foreign DNA fragments into the CRISPR locus, enabling adaptation to new viruses. We present crystal structures of...