CRISPR-Cas9 基因编辑机制图

生成一张 4:5 竖版「CRISPR-Cas9 基因编辑机制图」案例图，所属分类为「科研与学术图」。四格扁平矢量图，展示 CRISPR-Cas9 切割 DNA 的全过程，深蓝螺旋、灰色 Cas9 蛋白、琥珀色 PAM 位点及红绿结果分支。画面需要完整呈现上述主体、构图、配色、材质、光线和整体风格；可见文字以自然简体中文为主，必要的技术缩写、代码、变量名、学术符号、单位、拉丁物种名或装饰性外文可保留。

A Nature-journal-quality flat vector diagram illustrating the CRISPR-Cas9 gene-editing mechanism. The composition is horizontal, spanning roughly A4 landscape, divided into four sequential numbered panels connected by thin directional arrows. Panel 1 shows a double-stranded DNA helix in deep navy and sky blue, labelled "Target DNA" in clean sans-serif. Panel 2 depicts the Cas9 protein as a soft grey bi-lobed clamp with the guide RNA threading through it, annotated "sgRNA" with a dashed leader line. Panel 3 shows the Cas9-RNA complex binding and unwinding the DNA at the protospacer adjacent motif site, with the PAM sequence highlighted in amber. Panel 4 illustrates the double-strand break with blunt ends, and two diverging sub-panels: one showing Non-Homologous End Joining (NHEJ) as a red disrupted segment and one showing Homology-Directed Repair (HDR) as a green corrected segment. Color palette: white background, navy, sky-blue, slate-grey, amber accent, green and red only for outcome highlights. All text labels in Helvetica-style 9 pt. No gradients. Clean scientific illustration aesthetic consistent with Cell or Nature Methods figure panels.