Thekey differencebetween CRISPR and restriction enzymes is thatCRISPR是自然发生的prokaryoticimmune defense mechanism that has been recently used for eukaryotic gene editing and modification while限制性酶是将DNA分子切割成较小物质的生物剪刀。
Genome editing and基因修饰是遗传学和分子生物学方面有趣且创新的领域。基因治疗研究广泛使用基因修饰。此外,基因修饰可用于识别基因的特性,基因的功能以及基因中的突变如何影响其功能。得出有效和可靠的方法来对活细胞的基因组进行精确的,有针对性的更改非常重要。CRISPR和限制酶在基因修饰中起关键作用。CRISPR精确地修饰基因。限制性酶充当生物剪刀,将DNA分子切成较小的物质。
内容
1.Overview and Key Difference
2.什么是crispr
3.什么是限制性内切酶
4。CRISPR和限制酶之间的相似之处
5。Side by Side Comparison – CRISPR vs Restriction Enzymes in Tabular Form
6。概括
什么是crispr?
The CRISPR system is a natural mechanism present in some bacteria includingE. coliand Archea. It is an adaptive immune protection against foreign DNA-based invasions. Moreover, it is a sequence-specific mechanism. The CRISPR system contains several DNA repeat elements. These elements are interspersed with short “spacer” sequences derived from foreign DNA and multiple Cas genes. Some of the Cas genes are nucleases. Thus, the complete immune system is referred to as the CRISPR/Cas system.
The CRISPR/Cas system functions in four steps:
- 该系统在遗传上绑扎入侵噬菌体和质粒DNA片段(间隔者)进入CRISPR基因座(称为间隔者采集步骤)。
- crRNA maturation step – The host transcribes and processes CRISPR loci to generate mature CRISPR RNA (crRNA) containing both CRISPR repeat elements and the integrated spacer element.
- CRRNA通过互补的碱基对检测同源DNA序列。当存在感染并存在感染剂时,这一点很重要。
- 目标干扰步骤 - CRRNA检测到异物DNA,与外源DNA形成复合物,并保护宿主免受外源DNA的影响。
目前,CRISPR/CAS9系统用于通过转录抑制或激活来改变或修改哺乳动物基因组。哺乳动物细胞可以通过采用修复机制来应对CRISPR/CAS9介导的DNA断裂。可以使用非同源末端连接方法(NHEJ)或同源指导修复(HDR)完成。这两种修复机制都是通过引入双链休息而进行的。这导致哺乳动物基因编辑。NHEJ可以导致基因突变的消融,可用于造成功能效应的丧失。HDR可用于引入特定点突变或引入不同长度的DNA片段。目前,CRISPR/ CAS系统用于治疗,生物医学,农业和研究应用领域。
什么是限制酶?
A restriction enzyme, more commonly referred to as a restriction endonuclease, has the ability to cleave DNA molecules into small fragments. The cleaving process occurs near or at a special recognition site of the DNA molecule called a restriction site. A recognition site is typically composed of 4-8 base pairs. Depending on the site of cleavage, restriction enzymes can be of four (04) different types: Type I, Type II, Type III and Type IV. Other than the site of cleavage, factors such as composition, requirement of co-factors and the condition of the target sequence are taken into consideration when differentiating restriction enzymes into four groups.
在DNA分子的切割过程中,切割位点可以在限制位点本身或距限制位点的距离处。限制酶通过DNA双螺旋中的每个糖磷酸主链产生两个切口。
限制酶主要在ACHAEA和细菌中发现。他们利用这些酶作为针对入侵病毒的防御机制。限制酶裂解异物(致病)DNA,而不是其自己的DNA。它们自己的DNA受到称为甲基转移酶的酶的保护,该酶在宿主DNA中进行了修饰并防止裂解。
Type I restriction enzyme possesses a cleaving site which is away from the recognition site. Functioning of the enzyme requires ATP and the protein, S-adenosyl-L-methionine. Type I restriction enzyme is considered to be multifunctional due to the presence of both restriction and methylase activities. Type II restriction enzymes cleave within the recognition site itself or at a closer distance to it. It only requires magnesium (Mg) for its function. Type II restriction enzymes have only one function and are independent of methylase.
CRISPR和限制酶之间有什么相似之处?
- CRISPR和限制n enzymes are important tools in gene modification.
- CRISPR或CAS9的一部分以及限制酶是核酸内切酶。
- Both can recognize characteristic DNA sequences and cleave DNA.
- 它们存在于细菌和古细菌中。
- Both CRISPR and restriction enzymes are sequence-specific.
CRISPR和限制酶有什么区别?
CRISPR-Cas system is a prokaryotic immune system that confers resistance to foreign genetic elements. On the other hand, restriction enzymes are endonucleases that recognize a specific sequence of nucleotides and produce a double-stranded cut in the DNA. So, this is the key difference between CRISPR and restriction enzymes.
Moreover, CRISPR- allows extremely precise cuts. In comparison to that, restriction enzyme cleavage is less precise. Furthermore, CRISPR is an advanced technique while restriction enzymes are primitive.
Below infographic summarizes the difference between CRISPR and restriction enzymes.
概括– CRISPR vs Restriction Enzymes
CRISPR和限制n enzymes are two types of techniques used in gene modification. CRISPR is adaptive immune protection executed in some bacteria against foreign DNA based invasions. It is a natural defense mechanism. In contrast, restriction enzymes are endonucleases that cleave double-stranded DNA. Both CRISPR and restriction enzymes are able to cut DNA into small segments. However, both are sequence-specific. In comparison to CRISPR, restriction enzymes are primitive. CRISPR allows extremely precise cuts than restriction enzymes. So, this is the summary of the difference between CRISPR and restriction enzymes.
Reference:
Image Courtesy:
1. Boghog的“ 4Qyz” - 自己的作品(CC BY-SA 4.0)viaCommons Wikimedia
2.拉明·赫拉蒂(Ramin Herati)的“ ecorv限制性站点”Commons Wikimedia
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