Ladner S K, Miller T J, King R W
Avid Therapeutics, Inc., Philadelphia, Pennsylvania 19104, USA.
Antimicrob Agents Chemother. 1998 Aug;42(8):2128-31. doi: 10.1128/AAC.42.8.2128.
The cytosine analog 2'-deoxy-3'-thiacytidine (3TC) has been shown to be an effective treatment for chronic hepatitis B virus (HBV) infection. However, several liver transplant patients who were undergoing treatment with 3TC for HBV infection experienced a breakthrough of virus while on 3TC. The predominant virus found in these patients' sera contained either a valine or isoleucine for the methionine in the highly conserved YMDD nucleotide binding site in the HBV polymerase. To determine the biological relevance of the Met-to-Val substitution, we mutated a plasmid that contained a cDNA copy of the HBV pregenomic RNA such that when virus replication occurred during transient transfection of HepG2 cells, an M539V polymerase variant was produced. We found that in transiently transfected cells, this variant was approximately 330-fold less sensitive to the antiviral effects of 3TC and produced 7-fold less viral DNA than the wild type.
胞嘧啶类似物2'-脱氧-3'-硫代胞苷（3TC）已被证明是治疗慢性乙型肝炎病毒（HBV）感染的有效药物。然而，几名接受3TC治疗HBV感染的肝移植患者在使用3TC期间出现了病毒突破。在这些患者血清中发现的主要病毒在HBV聚合酶高度保守的YMDD核苷酸结合位点上，甲硫氨酸被缬氨酸或异亮氨酸取代。为了确定甲硫氨酸到缬氨酸替代的生物学相关性，我们对一个包含HBV前基因组RNA cDNA拷贝的质粒进行了突变，使得在HepG2细胞瞬时转染期间发生病毒复制时，产生M539V聚合酶变体。我们发现，在瞬时转染的细胞中，该变体对3TC抗病毒作用的敏感性比野生型低约330倍，产生的病毒DNA比野生型少7倍。
