State Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, 100084, Beijing, People's Republic of China.
Mol Biol Rep. 2010 Apr;37(4):2093-8. doi: 10.1007/s11033-009-9668-2. Epub 2009 Aug 11.
Trichosanthin (TCS) is a type I ribosome-inactivating protein with potent inhibitory activity against human immunodeficiency virus type 1. However, the anti-viral mechanism remains elusive. By a well-accepted HIV-1 integration assay, we demonstrated that TCS prevents HIV-1 DNA integration in a dose dependent manner in cell culture. At the same condition, TCS fails to induce obvious cytotoxicity and is also unable to interference viral early events such as viral entry, uncoating or reverse transcription. The HIV-1 integrase can integrate HIV-1 long-terminal repeats into cellular chromosome. The interaction of TCS with these viral integration components was also examined, indicating that TCS does not interact with HIV-1 integrase by the GST-pull down assay, but binds to the long terminal repeats in a transient manner. We further revealed that TCS can efficiently depurinate HIV-1 long-terminal repeats, which may be responsible for the inhibitory activity on HIV-1 integration. In conclusion, we elucidated that TCS specifically inhibits HIV-1 integration by depurinating the long-terminal repeats.
天花粉蛋白（TCS）是一种 I 型核糖体失活蛋白，对人类免疫缺陷病毒 1 型具有很强的抑制活性。然而，其抗病毒机制仍不清楚。通过一种被广泛接受的 HIV-1 整合测定方法，我们证明 TCS 在细胞培养中以剂量依赖的方式阻止 HIV-1 DNA 的整合。在相同条件下，TCS 不会引起明显的细胞毒性，也不能干扰病毒的早期事件，如病毒进入、脱壳或逆转录。HIV-1 整合酶可以将 HIV-1 长末端重复序列整合到细胞染色体中。我们还检查了 TCS 与这些病毒整合成分的相互作用，表明 GST 下拉测定法显示 TCS 不会与 HIV-1 整合酶相互作用，但以瞬时方式结合到长末端重复序列。我们进一步揭示 TCS 可以有效地使 HIV-1 长末端重复序列脱嘌呤，这可能是其抑制 HIV-1 整合活性的原因。总之，我们阐明了 TCS 通过脱嘌呤 HIV-1 长末端重复序列来特异性抑制 HIV-1 整合。
