Characterization of Megabat-Favored, CA-Dependent Susceptibility to Retrovirus Infection
Characterization of Megabat-Favored, CA-Dependent Susceptibility to Retrovirus Infection
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DOI：
10.1128/jvi.01803-22
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发表时间：
2023-02-13
影响因子：
5.4
通讯作者：
Morita，Rimpei
中科院分区：
文献类型：
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作者：
Ohkura，Sadayuki;Horie，Masayuki;Morita，Rimpei
从澳大利亚巨型蝙蝠中分离出考拉逆转录病毒样病毒，并在蝙蝠基因组中鉴定出内源性逆转录病毒，这就提出了蝙蝠对逆转录病毒易感性的问题。为了回答这个问题，我们研究了来自11种蝙蝠的12种细胞系对4种研究充分的逆转录病毒（人类和猿免疫缺陷病毒[HIV和SIV]和鼠白血病病毒[B-和N-MLV]）的易感性。蝙蝠之间的逆转录病毒易感性的系统比较显示，megabat细胞系总体上对四种逆转录病毒的敏感性低于microbat细胞系，特别是对HIV-1感染，而观察到MLV易感性的谱系特异性差异。逆转录（RT）产物的定量PCR、异核体细胞中的感染和衣壳（CA）的点突变分析显示：（i）HIV-1和MLV复制分别在整合前复合物的核转运处以及RT之前和/或RT期间被阻断，（ii）观察到的谱系特异性限制可归因于CA中特定位置限制的显性细胞因子。对先前报道的三种进入后限制因子的蝙蝠同源物的研究，这些限制因子受CA中相同残基的限制，即三重基序蛋白5α（TRIM 5 α）、粘病毒抗性2/B（Mx 2/Mx B）和羧基末端截短的切割和多聚腺苷酸化因子6（CPSF 6 -358）在megabat细胞中表现出较差的抗HIV-1活性，而megabat TRIM 5 α限制了MLV感染，这表明在蝙蝠细胞中观察到的对HIV-1的谱系特异性易感性中，主要的已知CA依赖性限制因子并不占主导地位。重要的是最近的研究已经证明了在澳大利亚的megabats和蝙蝠对HIV-1感染的抵抗力之间的γ逆转录病毒的循环;然而，这些病毒在megabats和蝙蝠的贡献逆转录病毒传播到其他哺乳动物物种的起源仍然不清楚。为了确定蝙蝠细胞对HIV-1感染的内在易感性，我们研究了从11种蝙蝠中分离的12种细胞系。我们报告，蝙蝠细胞系中的谱系特异性逆转录病毒限制可以归因于CA依赖因子。然而，在检查的megabat细胞系中，已知在灵长类细胞培养物中结合衣壳并阻断感染的因子，包括TRIM 5 α、Mx2/MxB和CPSF 6的同源物，未能表现出显著的抗HIV-1活性。这些结果表明，megabat细胞的HIV-1易感性以不同于灵长类细胞的方式发生，在灵长类细胞中，除了主要的已知CA依赖性限制因子之外，具有谱系特异性功能的细胞因子可以识别megabat中的逆转录病毒蛋白。
The isolation of the Koala retrovirus-like virus from Australian megabats and the identification of endogenous retroviruses in the bat genome have raised questions on bat susceptibility to retroviruses in general. To answer this, we studied the susceptibility of 12 cell lines from 11 bat species to four well-studied retroviruses (human and simian immunodeficiency viruses [HIV and SIV] and murine leukemia viruses [B- and N-MLV]). Systematic comparison of retroviral susceptibility among bats revealed that megabat cell lines were overall less susceptible to the four retroviruses than microbat cell lines, particularly to HIV-1 infection, whereas lineage-specific differences were observed for MLV susceptibility. Quantitative PCR of reverse transcription (RT) products, infection in heterokaryon cells, and point mutation analysis of the capsid (CA) revealed that (i) HIV-1 and MLV replication were blocked at the nuclear transport of the pre-integration complexes and before and/or during RT, respectively, and (ii) the observed lineage-specific restriction can be attributed to a dominant cellular factor constrained by specific positions in CA. Investigation of bat homologs of the three previously reported post-entry restriction factors constrained by the same residues in CA, tripartite motif-protein 5α (TRIM5α), myxovirus resistance 2/B (Mx2/MxB), and carboxy terminus-truncated cleavage and polyadenylation factor 6 (CPSF6-358), demonstrated poor anti-HIV-1 activity in megabat cells, whereas megabat TRIM5α restricted MLV infection, suggesting that the major known CA-dependent restriction factors were not dominant in the observed lineage-specific susceptibility to HIV-1 in bat cells. Therefore, HIV-1 susceptibility of megabat cells may be determined in a manner distinct from that of primate cells.IMPORTANCERecent studies have demonstrated the circulation of gammaretroviruses among megabats in Australia and the bats’ resistance to HIV-1 infection; however, the origins of these viruses in megabats and the contribution of bats to retrovirus spread to other mammalian species remains unclear. To determine the intrinsic susceptibility of bat cells to HIV-1 infection, we investigated 12 cell lines isolated from 11 bat species. We report that lineage-specific retrovirus restriction in the bat cell lines can be attributed to CA-dependent factors. However, in the megabat cell lines examined, factors known to bind capsid and block infection in primate cell culture, including homologs of TRIM5α, Mx2/MxB, and CPSF6, failed to exhibit significant anti-HIV-1 activities. These results suggested that the HIV-1 susceptibility of megabat cells occurs in a manner distinct from that of primate cells, where cellular factors, other than major known CA-dependent restriction factors, with lineage-specific functions could recognize retroviral proteins in megabats.