抗病毒和癌症基因组 DNA 脱氨酶 APOBEC3H 受 RNA 介导的二聚化机制调节。
The Antiviral and Cancer Genomic DNA Deaminase APOBEC3H Is Regulated by an RNA-Mediated Dimerization Mechanism.
机构信息
Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Center for Genome Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA.
出版信息
Mol Cell. 2018 Jan 4;69(1):75-86.e9. doi: 10.1016/j.molcel.2017.12.010. Epub 2017 Dec 28.
Human APOBEC3H and homologous single-stranded DNA cytosine deaminases are unique to mammals. These DNA-editing enzymes function in innate immunity by restricting the replication of viruses and transposons. APOBEC3H also contributes to cancer mutagenesis. Here, we address the fundamental nature of RNA in regulating human APOBEC3H activities. APOBEC3H co-purifies with RNA as an inactive protein, and RNase A treatment enables strong DNA deaminase activity. RNA-binding-defective mutants demonstrate clear separation of function by becoming DNA hypermutators. Biochemical and crystallographic data demonstrate a mechanism in which double-stranded RNA mediates enzyme dimerization. Additionally, APOBEC3H separation-of-function mutants show that RNA binding is required for cytoplasmic localization, packaging into HIV-1 particles, and antiviral activity. Overall, these results support a model in which structured RNA negatively regulates the potentially harmful DNA deamination activity of APOBEC3H while, at the same time, positively regulating its antiviral activity.
人类 APOBEC3H 和同源单链 DNA 胞嘧啶脱氨酶是哺乳动物所特有的。这些 DNA 编辑酶通过限制病毒和转座子的复制在先天免疫中发挥作用。APOBEC3H 也有助于癌症的诱变。在这里，我们研究了 RNA 调节人类 APOBEC3H 活性的基本性质。APOBEC3H 与 RNA 作为无活性的蛋白质共同纯化，并且 RNAse A 处理能够实现强大的 DNA 脱氨酶活性。RNA 结合缺陷突变体通过成为 DNA 超突变体表现出明显的功能分离。生化和晶体学数据表明，双链 RNA 介导酶二聚化的机制。此外，APOBEC3H 功能分离突变体表明，RNA 结合对于细胞质定位、包装到 HIV-1 颗粒中和抗病毒活性是必需的。总的来说，这些结果支持这样一种模型，即结构 RNA 负调控 APOBEC3H 潜在有害的 DNA 脱氨酶活性，同时正调控其抗病毒活性。
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