مروري بر ابزار كريسپر براي ويرايش ژنگان

An Overview on the Crisper Tools for Genome Editions

ﻛﺮﻳﺴﭙﺮ ﭼﻨﺪﻳﻦ دﻫﻪ ﭘﻴﺶ از آﻧﻜﻪ ﺑﻪ ﻋﻨﻮان ﺳﻴﺴﺘﻢ اﻳﻤﻨﻲ ﺑﺎﻛﺘﺮﻳﺎﻳﻲ و ﭘﺲ از آن ﺑﻪ ﻋﻨﻮان اﺑﺰاري ﻗﺪرﺗﻤﻨﺪ ﺑﺎ ﻗﺎﺑﻠﻴﺖ ﺑﺮﻧﺎﻣﻪ رﻳﺰي ﻣﺠﺪد ﺑﺮاي ﻫﺪف ﮔﻴﺮي ژن ﻣﻌﺮﻓﻲ ﺷﻮد، ﺑﻪ ﺳﺎدﮔﻲ ﺑﻪ ﻋﻨﻮان ﻳﻚ واﺣﺪ ﺗﻜﺮاري در DNA ﭘﺮوﻛﺎرﻳﻮﺗﻲ ﺷﻨﺎﺧﺘﻪ ﺷﺪه ﺑﻮد. ﻓﻨﺎوري وﻳﺮاﻳﺶ ژن ﻛﺮﻳﺴﭙﺮ داراي ﭘﺮوﺗﺌﻴﻦ ﻫﺎي ﻫﻤﺮاه Cas اﺳﺖ ﻛﻪ ﻓﻌﺎﻟﻴﺖ اﻧﺪوﻧﻮﻛﻠﺌﺎزي دارﻧﺪ و ﻣﻲ ﺗﻮاﻧﻨﺪ DNA ﻣﻮرد ﻧﻈﺮ را ﻃﺒﻖ دﺳﺘﻮري ﻛﻪ gRNA ﺑﻪ آنﻫﺎ ﻣﻲ دﻫﺪ ﺑﺮش ﺑﺰﻧﻨﺪ. در وﻳﺮاﻳﺶ ژن از روش ﻫﺎي HDR و NHEJ و وﻳﺮاﻳﺶ ﺑﺎز ﻧﻴﺰ اﺳﺘﻔﺎده ﻣﻲ ﺷﻮد ﻛﻪ در ﺑﻴﻦ آنﻫﺎ، وﻳﺮاﻳﺸﮕﺮﻫﺎي ﺑﺎز اﻣﺮوزه ﻣﻮرد ﺗﻮﺟﻪ ﺑﻴﺸﺘﺮي ﻗﺮار ﮔﺮﻓﺘﻪ اﻧﺪ؛ زﻳﺮا ﻣﻲ ﺗﻮاﻧﻨﺪ وراژﻧﮕﺎن )epigenome( را ﺑﺪون ﺷﻜﺴﺘﻦ DNA وﻳﺮاﻳﺶ ﻛﻨﻨﺪ. ﻛﺮﻳﺴﭙﺮ را ﺑﻪ ﻃﻮر ﻛﻠﻲ ﺑﻪ ﻛﻼسﻫﺎي I و II ﺗﻘﺴﻴﻢ ﻣﻲ ﻛﻨﻨﺪ. ﻻزم ﺑﻪ ذﻛﺮ اﺳﺖ ﻛﻪ ﻛﺮﻳﺴﭙﺮ ﻫﻨﻮز ﭼﺎﻟﺶ ﻫﺎي ﻓﻨﻲ زﻳﺎدي دارد و ﻣﻤﻜﻦ اﺳﺖ ﻣﺪت زﻣﺎن زﻳﺎدي ﻃﻮل ﺑﻜﺸﺪ ﺗﺎ ﻳﻚ اﺑﺰار ﻛﺮﻳﺴﭙﺮ ﺑﻲ ﻧﻘﺺ ﺗﻮﻟﻴﺪ ﺷﻮد. در اﻳﻦ ﻣﻘﺎﻟﻪ ﺑﻪ ﺗﻮﺿﻴﺢ ﻣﺤﺪودﻳﺖ ﻫﺎي ادﻏﺎم ژن، ﻋﻤﻠﻜﺮد ﻛﻠﻲ ﺳﻴﺴﺘﻢ ﻛﺮﻳﺴﭙﺮ و ﻫﻢ ﭼﻨﻴﻦ ﻣﻮارد اﺳﺘﻔﺎده از آن ﭘﺮداﺧﺘﻪ ﺷﺪه اﺳﺖ.

CRISPR had been simply known as a prokaryotic DNA repeated element for several decades before it was recognized as the bacterial immune system and subsequently harnessed as a powerful reprogrammable gene-targeting tool. The CRISPR gene-editing technology is composed of an endonuclease protein (CRISPR-associated (Cas9 protein) whose DNA-targeting specificity and cutting activity can be programmed by a short guide RNA. During the gene editing process; HDR, NHEJ and base editing pathways are used as well. Among these three, nowadays more attention paid to base editing as it can edit epigenome without any cleavages. Overall, there are two classes of CRISPR systems; class I and class II. Notably, CRISPR still has several technical challenges. It may take a long time until we develop a‘super’CRISPR tool that shows excellent efficiency. This article describes the overall performance of the Crisper system, its limitations and how it is used.