Drug Discovery Research, Astellas Pharma Inc., Miyukigaoka 21, Tsukuba, Ibaraki 305-8585, Japan.
Biochem Pharmacol. 2012 Aug 15;84(4):459-67. doi: 10.1016/j.bcp.2012.05.020. Epub 2012 Jun 9.
ASP2151 is an antiherpes agent targeting the helicase-primase complex of herpes simplex virus (HSV)-1, HSV-2, and varicella-zoster virus (VZV). We characterized the ASP2151-resistant HSV-1 and HSV-2 variants or mutants based on findings from sequencing analysis, growth, pathogenicity, and susceptibility testing, identifying several single base-pair substitutions resulting in amino acid changes in the helicase and primase subunit of ASP2151-resistant mutants. Amino acid alterations in the helicase subunit were clustered near helicase motif IV in the UL5 helicase gene of both HSV-1 and HSV-2, while the primase subunit substitution associated with reduced susceptibility, R367H, was found in ASP2151-resistant HSV-1 mutants. However, while susceptibility in the ASP2151-resistant HSV mutants to existing antiherpes agents was equivalent to that in wild-type HSV strains, ASP2151-resistant HSV mutants showed attenuated in vitro growth capability and in vivo pathogenicity compared with the parent strains. Taken together, our present findings demonstrated that important amino acid substitutions associated with reduced susceptibilities of HSV-1 and HSV-2 to ASP2151 exist in both the helicase and primase subunits of the helicase-primase complex, and that mutations in this complex against ASP2151 might confer defects in viral replication and pathogenicity.
ASP2151 是一种抗疱疹病毒药物，靶向单纯疱疹病毒 (HSV)-1、HSV-2 和水痘带状疱疹病毒 (VZV) 的解旋酶-引发酶复合物。我们根据测序分析、生长、致病性和药敏试验的结果，对耐 ASP2151 的 HSV-1 和 HSV-2 变体或突变体进行了特征描述，发现了几个导致 ASP2151 耐药突变体中解旋酶和引发酶亚基氨基酸变化的单一碱基替换。HSV-1 和 HSV-2 的 UL5 解旋酶基因中，解旋酶亚基的氨基酸改变聚集在解旋酶基序 IV 附近，而与耐药相关的引发酶亚基替换 R367H 则存在于耐 ASP2151 的 HSV-1 突变体中。然而，虽然耐 ASP2151 的 HSV 突变体对现有抗疱疹病毒药物的敏感性与野生型 HSV 株相当，但与亲本株相比，耐 ASP2151 的 HSV 突变体在体外生长能力和体内致病性方面均有所减弱。总之，我们目前的研究结果表明，与 HSV-1 和 HSV-2 对 ASP2151 的敏感性降低相关的重要氨基酸替换存在于解旋酶-引发酶复合物的解旋酶和引发酶亚基中，该复合物中的突变可能导致病毒复制和致病性缺陷。
