Endocytosis is a critical step in entry of subgroup B avian leukosis viruses
Endocytosis is a critical step in entry of subgroup B avian leukosis viruses
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DOI：
10.1128/jvi.76.24.12866-12876.2002
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发表时间：
2002-12-01
影响因子：
5.4
通讯作者：
Brojatsch, J
中科院分区：
文献类型：
--
作者：
Diaz-Griffero, F;Hoschander, SA;Brojatsch, J
禽白血病病毒（ALV）的进入机制是有争议的，有证据支持和反对病毒融合的低pH要求。为了进一步解决这个问题，我们测试了在三种不同的亲溶酶体剂存在下，用B亚群ALV（ALV-B）的包膜蛋白假型化的人类免疫缺陷病毒1型（HIV-1）的进入。这些亲溶酶体剂能够阻断两种不同细胞系中野生型和假型ALV-B的进入，强烈表明ALV-B需要低pH步骤才能进入。ALV-B和pH依赖性Semliki森林病毒（SFV）进入细胞的吸收动力学比HIV-1慢，这是pH无关的。这些缓慢的摄取速率支持ALV-B利用内吞途径进入细胞的理论。使用免疫荧光和电子显微镜分析，我们可视化的共定位的病毒颗粒与内体标记转铁蛋白和网格蛋白包被的囊泡和内体样结构中的病毒颗粒。令人惊讶的是，低pH值的治疗并没有克服ALV-B进入溶酶体剂的抑制。这表明，相比SFV，ALV-B是无法融合在细胞表面，即使在低pH值。总之，我们的研究结果表明，内吞作用和随后的低pH值步骤是成功ALV-B感染的关键。
The avian leukosis virus (ALV) entry mechanism is controversial, with evidence for and against a low-pH requirement for viral fusion. To further address this question, we tested the entry of human immunodeficiency virus type 1 (HIV-1) pseudotyped with the envelope protein of subgroup B ALV (ALV-B) in the presence of three different lysosomotropic agents. These lysosomotropic agents were able to block the entry of wild-type and pseudotyped ALV-B in two different cell lines, strongly suggesting that ALV-B requires a low-pH step for entry. ALV-B and pH-dependent Semliki Forest virus (SFV) entered cells with slower uptake kinetics than HIV-1, which is pH independent. These slow uptake rates support the theory that ALV-B utilizes endocytic pathways to enter cells. Using immunofluorescence and electron microscopy analysis, we visualized the colocalization of virus particles with the endosomal marker transferrin and demonstrated virus particles in clathrin-coated vesicles and endosome-like structures. Surprisingly, a low-pH treatment did not overcome the inhibition of ALV-B entry by lysosomotropic agents. This indicates that, in contrast to SFV, ALV-B is unable to fuse at the cellular surface, even at a low pH. Taken together, our findings suggest that endocytosis and a subsequent low-pH step are critical for successful ALV-B infection.