RNase L-independent specific 28S rRNA cleavage in murine coronavirus-infected cells
RNase L-independent specific 28S rRNA cleavage in murine coronavirus-infected cells
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DOI：
10.1128/jvi.74.19.8793-8802.2000
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发表时间：
2000-10-01
影响因子：
5.4
通讯作者：
Makino, S
中科院分区：
文献类型：
--
作者：
Banerjee, S;An, SW;Makino, S
我们在感染小鼠冠状病毒小鼠肝炎病毒（MHV）的细胞中发现了一种新的28S rRNA切割。在min感染的DBT细胞中，28S rRNA早在感染后4小时就发生了切割，随着感染次数的增加，28S rRNA的完整量减少，随后出现了切割产物；几乎所有完整的28S rRNA在24小时内消失。相比之下，在感染细胞中没有检测到特异性的18S rRNA切割。在所有MHV易感细胞系和所有测试的MHV株中均检测到MHV诱导的28S rRNA切割。28S rRNA的切割需要MHV复制，成熟的细胞质28S rRNA进行了切割。在某些细胞和病毒的组合中，用干扰素预处理病毒感染的细胞，激活细胞核糖核酸内切酶RNase L，导致rRNA降解。用于MHV感染的接种物中未检测到干扰素。在mhv感染的细胞中加入抗干扰素抗体并没有抑制28S rRNA的切割。此外，28S rRNA切割发生在由RNase L敲除小鼠衍生的mhv感染小鼠胚胎成纤维细胞系中。因此，mhv诱导的28S rRNA切割与RNase l的激活无关，也不同于细胞凋亡相关的rRNA降解，后者通常伴随着DNA的断裂。在mhv感染的17Cl-1细胞中，28S rRNA的切割比DNA断裂至少早18小时。用caspase抑制剂处理mhv感染的17Cl-1细胞，阻断细胞凋亡并没有阻断28S rRNA的切割。此外，MHV诱导的28S rRNA切割发生在mw感染的DBT细胞中，不表现出凋亡迹象，包括caspase-3的激活和DNA断裂。因此，mhv诱导的28S rRNA切割似乎不同于之前描述的任何rRNA降解机制。
We characterized a novel 28S rRNA cleavage in cells infected with the murine coronavirus mouse hepatitis virus (MHV). The 28S rRNA cleavage occurred as early as 4 h postinfection (p.i.) in MIN-infected DBT cells, with the appearance of subsequent cleavage products and a decrease in the amount of intact 28S rRNA with increasing times of infection; almost all of the intact 28S rRNA disappeared by 24 h p.i. In contrast, no specific 18S rRNA cleavage was detected in infected cells. MHV-induced 28S rRNA cleavage was detected in all MHV-susceptible cell lines and all MHV strains tested. MHV replication was required for the 28S rRNA cleavage, and mature cytoplasmic 28S rRNA underwent cleavage. In certain combination of cells and viruses, pretreatment of virus-infected cells with interferon activates a cellular endoribonuclease, RNase L, that causes rRNA degradation. No interferon was detected in the inoculum used for MHV infection. Addition of antiinterferon antibody to MHV-infected cells did not inhibit 28S rRNA cleavage. Furthermore, 28S rRNA cleavage occurred in an MHV-infected mouse embryonic fibroblast cell line derived from RNase L knockout mice. Thus, MHV-induced 28S rRNA cleavage was independent of the activation of RNase L. MHV-induced 28S rRNA cleavage,vas also different from apoptosis-related rRNA degradation, which usually occurs concomitantly with DNA fragmentation. In MHV-infected 17Cl-1 cells, 28S rRNA cleavage preceded DNA fragmentation by at least 18 h. Blockage of apoptosis in MHV-infected 17Cl-1 cells by treatment with a caspase inhibitor did not block 28S rRNA cleavage. Furthermore, MHV induced 28S rRNA cleavage occurred in MW-infected DBT cells that do not show apoptotic signs, including activation of caspase-3 and DNA fragmentation. Thus, MHV-induced 28S rRNA cleavage appeared to differ from any rRNA degradation mechanism described previously.