Gu Qinyong, Zhang Zeli, Cano Ortiz Lucía, Franco Ana Cláudia, Häussinger Dieter, Münk Carsten
Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany.
Laboratory of Virology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
J Virol. 2016 Nov 14;90(23):10545-10557. doi: 10.1128/JVI.01593-16. Print 2016 Dec 1.
Feline immunodeficiency virus (FIV) Vif protein counteracts feline APOBEC3s (FcaA3s) restriction factors by inducing their proteasomal degradation. The functional domains in FIV Vif for interaction with FcaA3s are poorly understood. Here, we have identified several motifs in FIV Vif that are important for selective degradation of different FcaA3s. Cats (Felis catus) express three types of A3s: single-domain A3Z2, single-domain A3Z3, and double-domain A3Z2Z3. We proposed that FIV Vif would selectively interact with the Z2 and the Z3 A3s. Indeed, we identified two N-terminal Vif motifs (12LF13 and 18GG19) that specifically interacted with the FcaA3Z2 protein but not with A3Z3. In contrast, the exclusive degradation of FcaA3Z3 was regulated by a region of three residues (M24, L25, and I27). Only a FIV Vif carrying a combination of mutations from both interaction sites lost the capacity to degrade and counteract FcaA3Z2Z3. However, alterations in the specific A3s interaction sites did not affect the cellular localization of the FIV Vif protein and binding to feline A3s. Pulldown experiments demonstrated that the A3 binding region localized to FIV Vif residues 50 to 80, outside the specific A3 interaction domain. Finally, we found that the Vif sites specific to individual A3s are conserved in several FIV lineages of domestic cat and nondomestic cats, while being absent in the FIV Vif of pumas. Our data support a complex model of multiple Vif-A3 interactions in which the specific region for selective A3 counteraction is discrete from a general A3 binding domain.
Both human immunodeficiency virus (HIV) and feline immunodeficiency virus (FIV) Vif proteins counteract their host's APOBEC3 restriction factors. However, these two Vif proteins have limited sequence homology. The molecular interaction between FIV Vif and feline APOBEC3s are not well understood. Here, we identified N-terminal FIV Vif sites that regulate the selective interaction of Vif with either feline APOBEC3Z2 or APOBEC3Z3. These specific Vif sites are conserved in several FIV lineages of domestic cat and nondomestic cats, while being absent in FIV Vif from puma. Our findings provide important insights for future experiments describing the FIV Vif interaction with feline APOBEC3s and also indicate that the conserved feline APOBEC3s interaction sites of FIV Vif allow FIV transmissions in Felidae.
猫免疫缺陷病毒（FIV）的Vif蛋白通过诱导猫载脂蛋白B mRNA编辑酶催化多肽样蛋白3（FcaA3s）的蛋白酶体降解来对抗其限制因子。FIV Vif中与FcaA3s相互作用的功能域尚不清楚。在这里，我们在FIV Vif中鉴定出几个基序，它们对不同FcaA3s的选择性降解很重要。猫（Felis catus）表达三种类型的A3s：单结构域A3Z2、单结构域A3Z3和双结构域A3Z2Z3。我们推测FIV Vif会选择性地与Z（2）和Z（3）A3s相互作用。事实上，我们鉴定出两个N端Vif基序（12LF13和18GG19），它们与FcaA3Z2蛋白特异性相互作用，但不与A3Z3相互作用。相反，FcaA3Z3的特异性降解由三个残基（M24、L25和I27）的区域调节。只有携带来自两个相互作用位点的突变组合的FIV Vif失去了降解和对抗FcaA3Z2Z3的能力。然而，特定A3s相互作用位点的改变并不影响FIV Vif蛋白的细胞定位以及与猫A3s的结合。下拉实验表明，A3结合区域定位于FIV Vif的50至80位残基，在特定A3相互作用域之外。最后，我们发现特定于单个A3s的Vif位点在几种家猫和非家猫的FIV谱系中是保守的，而在美洲狮的FIV Vif中不存在。我们的数据支持一个复杂的多Vif-A3相互作用模型，其中选择性A3对抗的特定区域与一般A3结合域是分开的。
人类免疫缺陷病毒（HIV）和猫免疫缺陷病毒（FIV）的Vif蛋白都能对抗其宿主的载脂蛋白B mRNA编辑酶催化多肽样蛋白3（APOBEC3）限制因子。然而，这两种Vif蛋白的序列同源性有限。FIV Vif与猫APOBEC3s之间的分子相互作用尚不清楚。在这里，我们鉴定了FIV Vif的N端位点，这些位点调节Vif与猫APOBEC3Z2或APOBEC3Z3的选择性相互作用。这些特定的Vif位点在几种家猫和非家猫的FIV谱系中是保守的，而在美洲狮的FIV Vif中不存在。我们的发现为未来描述FIV Vif与猫APOBEC3s相互作用的实验提供了重要的见解，也表明FIV Vif保守的猫APOBEC3s相互作用位点允许FIV在猫科动物中传播。
