Induction of Caspase Activation and Cleavage of the Viral Nucleocapsid Protein in Different Cell Types during Crimean-Congo Hemorrhagic Fever Virus Infection
Induction of Caspase Activation and Cleavage of the Viral Nucleocapsid Protein in Different Cell Types during Crimean-Congo Hemorrhagic Fever Virus Infection
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DOI：
10.1074/jbc.m110.149369
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发表时间：
2011-02-04
影响因子：
4.8
通讯作者：
Mirazimi, Ali
中科院分区：
文献类型：
--
作者：
Karlberg, Helen;Tan, Yee-Joo;Mirazimi, Ali
已经观察到几种病毒病原体在感染期间的细胞凋亡调节。响应病毒感染的程序性细胞死亡和细胞凋亡的调节是宿主或病毒存活的重要因素。目前尚不清楚克里米亚-刚果出血热病毒（CCHFV）感染是否在体外调节细胞凋亡过程。本研究首次表明CCHFV诱导细胞凋亡，这可能依赖于caspase-3的激活。本研究还表明，CCHFV的S片段的编码序列含有一个蛋白水解酶切位点DEVD，这是所有CCHFV株中保守的。通过使用不同的重组表达系统和定点突变，我们证明了这个基序是受半胱天冬酶切割。我们还表明，CCHFV核衣壳蛋白（NP）被切割成一个30 kDa的片段，在同一时间作为半胱天冬酶活性诱导感染过程中。使用半胱天冬酶抑制剂和缺乏半胱天冬酶-3的细胞，我们清楚地表明，NP的裂解是半胱天冬酶-3依赖性的。我们还表明，抑制凋亡诱导的子代病毒滴度类似于80- 90%。因此，NP的半胱天冬酶-3依赖性裂解可能代表了宿主对裂解性CCHFV感染的防御机制。总之，这些数据表明，CCHFV的最丰富的蛋白质，它具有几个基本功能，如保护病毒RNA和参与复制周期中的各种过程，可以受到宿主细胞半胱天冬酶切割。
Regulation of apoptosis during infection has been observed for several viral pathogens. Programmed cell death and regulation of apoptosis in response to a viral infection are important factors for host or virus survival. It is not known whether Crimean-Congo hemorrhagic fever virus (CCHFV) infection regulates the apoptosis process in vitro. This study for the first time suggests that CCHFV induces apoptosis, which may be dependent on caspase-3 activation. This study also shows that the coding sequence of the S segment of CCHFV contains a proteolytic cleavage site, DEVD, which is conserved in all CCHFV strains. By using different recombinant expression systems and site-directed mutagenesis, we demonstrated that this motif is subject to caspase cleavage. We also demonstrate that CCHFV nucleocapsid protein (NP) is cleaved into a 30-kDa fragment at the same time as caspase activity is induced during infection. Using caspase inhibitors and cells lacking caspase-3, we clearly demonstrate that the cleavage of NP is caspase-3-dependent. We also show that the inhibition of apoptosis induced progeny viral titers of similar to 80-90%. Thus, caspase-3-dependent cleavage of NP may represent a host defense mechanism against lytic CCHFV infection. Taken together, these data suggest that the most abundant protein of CCHFV, which has several essential functions such as protection of viral RNA and participation in various processes in the replication cycle, can be subjected to cleavage by host cell caspases.