抗病毒治疗是慢性乙型肝炎（CHB）治疗的首选，但对大多数CHB患者而言，抗病毒药物不可能清除HBV，因此CHB根治成为奢望。而清除宿主细胞核内HBV共价闭合环状DNA（cccDNA）是治愈CHB关键。HBV X基因有反式激活作用，可促进HBV复制。PreS1 N端氨基酸与肝细胞表面钠离子--牛磺胆酸共转运蛋白（NTCP）受体特异性结合，是HBV进入细胞的关键。我们发现CRISPR/Cas系统靶向X区，有降低细胞核内cccDNA、抑制HBV复制及HBsAg和HBeAg表达的作用。我们的研究将涵盖PreS1区、X区和NTCP基因的69个靶点，观察CRISPR/Cas系统联合切割S区、X区和NTCP基因的单一或多个靶点后，能否最大程度的减少HBV进入细胞以及降解细胞核内cccDNA，为抗病毒治疗提供新思路。

Antiviral therapy is the first choice for chronic hepatitis B virus (CHB). Antiviral drugs could not eradicate HBV and it is impossible for complete cure. The key point for curing CHB is eradicate covalently closed circular DNA（cccDNA）in nucleus. HBV X gene enhance HBV replication by trans-activation. N terminal amino acid of PreS1 could combine with specific receptor Sodium taurocholate co-transporting polypeptide (NTCP) on hepatocyte, which is the key point of HBV entry host cell. We observed CRISPR/Cas system targeting X region which could bring effect in reducing cccDNA in nucleus, inhibiting HBV replication, and decreasing HBsAg and HBeAg. We will research CRISPR/Cas system editing all 69 targets on PreS1 region, X region and NTCP genome, observe whether the inhibition of HBV cellular entry or degradation nuclear cccDNA markedly on one or/and three target, and provide new direction for antiviral therapy.