SIMIAN-VIRUS 40 AGNOPROTEIN FACILITATES PERINUCLEAR-NUCLEAR LOCALIZATION OF VP1, THE MAJOR CAPSID PROTEIN
SIMIAN-VIRUS 40 AGNOPROTEIN FACILITATES PERINUCLEAR-NUCLEAR LOCALIZATION OF VP1, THE MAJOR CAPSID PROTEIN
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DOI：
10.1128/jvi.60.3.1055-1061.1986
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发表时间：
1986-12-01
影响因子：
5.4
通讯作者：
ALWINE, JC
中科院分区：
文献类型：
--
作者：
CARSWELL, S;ALWINE, JC
猴病毒40（SV 40）的未知蛋白是一个由61个氨基酸组成的蛋白质，编码于一些晚期mRNA的前导序列中。在对SV 40衣壳蛋白的抗血清的间接免疫荧光研究中，我们发现，突变体，使没有agnoprotein显示异常的核周核定位的VP 1，主要的衣壳蛋白，但不是VP 2或VP 3，次要的衣壳蛋白。在野生型（WT）SV 40感染的CV-1 P细胞中，VP 1主要存在于细胞质中，直至感染后36 h（p.i.）， 大约是在我们的感染条件下检测到高水平的未知蛋白的时间。此后，VPI迅速定位于核周区和核。相比之下，在不含未知蛋白的突变体感染的CV-1 P细胞中，VP 1的核周-核积聚效率低得多;在感染后48 h观察到以胞质荧光为主的细胞比例显著更大。在48和60 h p.i.与WT感染的对照组相比，观察到更多的细胞具有大量的核周染色和很少的核染色。在对组成型表达未知蛋白的稳定转染细胞系的类似分析中，VP 1在感染后30小时前定位于细胞核，不管感染的是什么病毒在一个突变体，使没有未知蛋白的VP 1的延迟核进入也克服了在回复突变体，其中有一个第二个位点点突变的VP 1。这表明VP 1的改变可以通过提高其自身核定位率来部分克服未知基因突变的缺陷。总之，这些结果表明，至少一个功能的未知蛋白是提高效率的核周核定位的VP 1。
The agnoiprotein of simian virus 40 (SV40) is a 61-amino-acid protein encoded in the leader of some late mRNAs. In indirect immunofluorescence studies with antisera against SV40 capsid proteins, we show that mutants which make no agnoprotein display abnormal perinuclear-nuclear localization of VP1, the major capsid protein, but not VP2 or VP3, the minor capsid proteins. In wild-type (WT) SV40-infected CV-1P cells, VP1 was found predominantly in the cytoplasm until 36 h postinfection (p.i.), approximately the time that high levels of agnoprotein became detectable under our infection conditions. Thereafter, VPI localized rapidly to the perinuclear region and to the nucleus. In contrast, in agnoprotein-minus mutant-infected CV-1P cells, perinuclear-nuclear accumulation of VP1 occurred much less efficiently; a significantly greater fraction of cells with predominantly cytoplasmic fluorescence was observed up to 48 h p.i. At 48 and 60 h p.i. more cells with largely perinuclear and little nuclear staining were seen than in WT-infected controls. In similar analyses with stably transfected cell lines constitutively expressing the agnoprotein, VP1 localized to the nucleus before 30 h p.i., regardless of the infecting virus. Delayed nuclear entry of VP1 in a mutant which makes no agnoprotein was also overcome in a revertant which has a second site point mutation in VP1. This suggests that an alteration of VP1 can partially overcome the defect ofthe agnogene mutation by enhancement of the rate of its own nuclear localization. Taken together, these results indicate that a least one function of the agnoprotein is to enhance the efficiency of perinuclear-nuclear localization of VP1.