Disassociation of the SV40 genome from capsid proteins prior to nuclear entry.
Disassociation of the SV40 genome from capsid proteins prior to nuclear entry.
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DOI：
10.1186/1743-422x-9-158
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发表时间：
2012-08-10
期刊：
影响因子：
4.8
通讯作者：
Norkin LC
中科院分区：
文献类型：
--
作者：
Kuksin D;Norkin LC
以前，我们证明了输入SV 40颗粒在内质网中进行部分拆卸，这暴露了内部衣壳蛋白VP 2和VP 3的免疫染色。然后，在细胞质中，拆卸进一步进行，也使基因组DNA可用于免疫检测，以及通过基于乙炔基-2-脱氧尿苷（EdU）的化学反应进行检测。除了病毒基因组外，细胞质部分分解的SV 40颗粒保留了一些SV 40衣壳蛋白VP 1、VP 2和VP 3。在目前的研究中，我们询问了细胞中SV 40基因组可能与衣壳组分分离的位置。我们观察到细胞核周围部分分解的输入SV 40颗粒，并且从感染后12小时开始，5-溴-2-脱氧尿苷（BrdU）标记的亲本SV 40 DNA在细胞核中，如使用抗BrdU抗体检测到的。然而，在检测的1500多个细胞中，我们从未在细胞核中检测到输入VP 2/VP 3。在BrdU标记的SV 40基因组易位到细胞核中时，它们被转录，因此代表了生产性感染。我们的研究结果表明，SV 40基因组在进入细胞核之前或进入细胞核时与衣壳蛋白分离，然后进入缺乏VP 2/3的细胞核。
Previously, we demonstrated that input SV40 particles undergo a partial disassembly in the endoplasmic reticulum, which exposes internal capsid proteins VP2 and VP3 to immunostaining. Then, in the cytoplasm, disassembly progresses further to also make the genomic DNA accessible to immune detection, as well as to detection by an ethynyl-2-deoxyuridine (EdU)-based chemical reaction. The cytoplasmic partially disassembled SV40 particles retain some of the SV40 capsid proteins, VP1, VP2, and VP3, in addition to the viral genome. In the current study, we asked where in the cell the SV40 genome might disassociate from capsid components. We observed partially disassembled input SV40 particles around the nucleus and, beginning at 12 hours post-infection, 5-Bromo-2-deoxyuridine (BrdU)-labeled parental SV40 DNA in the nucleus, as detected using anti-BrdU antibodies. However, among the more than 1500 cells examined, we never detected input VP2/VP3 in the nucleus. Upon translocation of the BrdU-labeled SV40 genomes into nuclei, they were transcribed and, thus, are representative of productive infection. Our findings imply that the SV40 genome disassociates from the capsid proteins before or at the point of entry into the nucleus, and then enters the nucleus devoid of VP2/3.