The Double Nickase Plasmid features a U6 promoter for sgRNA expression, a 20 nt targeting sequence, and a gRNA scaffold to guide Cas9n. It includes a CBh promoter for Cas9n (D10A) and puromycin resistance, GFP for transfection verification, and nuclear localization signals (NLS). The 2A peptide allows co-expression of Cas9n and Puro from a single promoter, enabling precise genome editing with reduced off-target effects.
The Double Nickase Plasmid features a U6 promoter for sgRNA expression, a 20 nt targeting sequence, and a gRNA scaffold to guide Cas9n. It includes a CBh promoter for Cas9n (D10A) and puromycin resistance, GFP for transfection verification, and nuclear localization signals (NLS). The 2A peptide allows co-expression of Cas9n and Puro from a single promoter, enabling precise genome editing with reduced off-target effects.
Cas9n Nickase gRNA Plasmid Targeting: Dual gRNA plasmids create single-strand nicks at precise DNA sequences for efficient genome editing using Cas9n Nickase.
This image illustrates the Cas9n Nickase mechanism used for precise genome editing. Two plasmids (Plasmid 1 and Plasmid 2) are shown, each containing a targeted DNA sequence. The system utilizes single-guide RNAs (sgRNA) to direct Cas9n Nickase to specific genomic locations, represented by the blue and pink DNA strands. The sgRNA scaffold aids in guiding Cas9n to the 20 nucleotide (nt) target sequence on the DNA. Cas9n makes single-strand cuts at NCC and NGG sites, enabling precise gene modifications without creating double-strand breaks.
The Double Nickase Plasmid features a U6 promoter for sgRNA expression, a 20 nt targeting sequence, and a gRNA scaffold to guide Cas9n. It includes a CBh promoter for Cas9n (D10A) and puromycin resistance, GFP for transfection verification, and nuclear localization signals (NLS). The 2A peptide allows co-expression of Cas9n and Puro from a single promoter, enabling precise genome editing with reduced off-target effects.
MEST 编码印记基因“父源表达基因 1”(Peg1)蛋白,这是一种受发育阶段调控的因子,参与胚胎生长控制以及间充质谱系的生物学过程。Peg1 与印记位点的表观遗传调控相关,常在 DNA 甲基化与染色质状态维持的研究背景下被关注,这些过程共同塑造细胞命运决定。MEST 的表达水平或印记状态发生改变,已被发现与分化程序失衡、代谢表型异常以及与肿瘤相关的表观遗传重塑有关。作为“母源沉默/父源表达”的基因,MEST 也是研究亲本来源效应、等位基因特异性表达,以及在细胞应激或转化条件下印记不稳定性的有用模型。
Peg1 双切酶质粒(h)由一对匹配的质粒组成,专为在 human 细胞系中对 MEST 位点进行高特异性编辑而设计。每个质粒分别表达Cas9 D10A切口酶和针对MEST内不同DNA链的独特sgRNA。当这两种切口酶被引导至相邻但位于DNA链相反侧的位点时,会产生错位的单链切口,从而共同形成错位双链断裂,这需要两个引导RNA在靶位点上协同发挥作用。由此产生的DNA断裂通过内源性细胞修复途径(最常见的是非同源末端连接(NHEJ))得到修复,从而导致插入或缺失,进而破坏MEST的功能。通过要求双sgRNA在靶位点结合,双切口方法提高了编辑特异性,并为需要对靶向精度进行额外控制的应用提供了互补的CRISPR策略。