臺灣博碩士論文加值系統

C型肝炎病毒 (Hepatitis C virus, HCV) 非結構性蛋白質NS4A具有54個胺基酸，分子量為6 kDa。主要在作為NS3 serine protease的輔因子，促使多蛋白質前驅物的切割。NS4A也可利用自身中央區域和NS3作用，活化NS3 serine protease並促使NS3的內部截切。最近的研究發現，NS4A單獨存在時會累積在細胞內的粒線體中，並經由粒線體相關的路徑引發細胞凋亡以及活化caspase-3。先前本實驗室以cDNA microarray分析HCV subgenomic replicon細胞株，發現在HCV非結構性蛋白質表現時，clusterin (CLU) mRNA有上升的情形。CLU是一個廣泛分布於組織與體液的醣蛋白質。先前研究指出CLU和DNA修復以及細胞凋亡或存活等功能相關。全長的CLU mRNA經由選擇性剪修 (alternative splicing) 可產生不同長度mRNA並分別轉譯出兩種不同功能的同型體，secreted clusterin (sCLU) 以及 nuclear clusterin (nCLU)。
本研究首先將單一HCV非結構性蛋白質表現質體轉染293細胞，抽取RNA藉由即時定量聚合酶反應分析，發現NS4A和NS5B均會特異性地增加細胞內CLU mRNA的量。NS4A增加細胞內sCLU mRNA的量，而對nCLU mRNA的表現則沒有明顯的影響。當共轉染NS4A表現質體和含有801 bp CLU 啟動子長度的pCLU-luc報導質體到293細胞時，分析luciferase 的mRNA合成量，發現比起控制組並無明顯改變，顯示NS4A可能並非影響在CLU mRNA的合成上，或者NS4A作用位置不在801 bp CLU 啟動子的範圍內。以上結果也可推測：NS4A增加細胞內CLU mRNA的機制可能是經由抑制 CLU mRNA的分解，亦即增加CLU mRNA的穩定度。在蛋白質層次方面，表現NS4A的293細胞，細胞內的sCLU和precursor nCLU (pnCLU) 均有增加，但分泌至細胞培養液中的sCLU反而下降，推測NS4A降低293細胞中sCLU蛋白質的穩定性。而在可經doxycycline誘導表現NS3-4A的HepG22-NS3-4A穩定細胞株，其細胞內及細胞外的sCLU有微幅的增加，是否NS3的共同表現會影響NS4A對CLU表現之調控則有待進一步確認。另一方面，分析NS4A參與caspase-3活化的重要區域。刪除突變株NS4A(1-34) 則失去了促使caspase-3活化的特性。無論是NS4A(35-54) 刪除突變株或是NS4A中央區域的點突變株均仍保有活化caspase-3的能力，而NS4A(35-54) 活化caspase-3的能力略為下降。分析NS4A影響CLU基因表現以及活化caspase-3 的特性有助於了解HCV感染時，病毒與宿主之間的關係。

Hepatitis C virus (HCV) NS4A is a nonstructural protein of about 6 kDa that consists of 54 amino acids. The well-known function of NS4A is the cofactor of NS3 serine protease that promotes the HCV polyprotein processing. NS4A also uses its central domain to interact with NS3 serine protease and to promote NS3 internal cleavage. A recent study demonstrated that NS4A accumulates on mitochondria membrane and induces mitochondria-mediated cell apoptosis and caspase-3 activation. cDNA microarray analysis from our laboratory revealed an increase of clusterin (CLU) mRNA in HCV subgenomic replicon cell line. CLU is a glycoprotein that expresses in virtually all tissue and fluid. CLU is associated with DNA repair, cell apoptosis and cell survival. It has two distinct isoforms: the secreted CLU (sCLU) and nuclear CLU (nCLU). sCLU and nCLU are translated from full-length CLU mRNA and alternatively spliced CLU mRNA, respectively.
In this study, HCV nonstructural protein expression plasmids were transfected into 293 cells. RNA was isolated for quantitative PCR analysis. Results showed that expression of NS4A or NS5B alone specifically increased cellular steady-state CLU mRNA. NS4A could increase cellular sCLU mRNA but it had little influence on nCLU expression. NS4A expression plasmid was co-transfected with pCLU-luc reporter plasmid containing 801 bp of CLU promoter into 293 cells. RNA was extracted for RT-PCR analysis. The synthesis of luciferase mRNA in NS4A-transfected cells was not significantly different from that in vector-transfected cells. These data suggest that NS4A has no influence on the promoter activity of clusterin or NS4A-responsive elements are beyond the cloned 801 bp region. These results indicate that the mechanism of NS4A-mediated upregulation of CLU mRNA may be through inhibition of CLU mRNA degradation. The level of sCLU protein in cell lysates was increased, but sCLU protein in medium was decreased in NS4A-transfected 293 cells. These results suggest that NS4A may decrease sCLU stability in 293 cells. Furthermore, sCLU protein was slightly increased both in the cell lysates and the culture medium of doxycycline-induced HepG22-NS3-4A stable cells. On the other hand, important sequences of NS4A involved in the enhancement of caspase-3 activity were analyzed. Deletion mutant NS4A(1-34) lost the ability to activate caspase-3 activity, indicating that NS4A(35-54) domain is important for caspase-3 activation. Understanding the NS4A-mediated CLU regulation and the important domain of NS4A involved in caspase-3 activation will help us to elucidate the interaction between host and virus during HCV infection.

口試委員會審書 i
中文摘要 ii
英文摘要 iii
目錄 v
表目錄 vii
圖目錄 viii
第一章 緒論 1
一、C型肝炎病毒的發現歷史及分類 1
二、C型肝炎病毒的基因體結構及功能 2
三、C型肝炎病毒非結構性蛋白質NS4A的功能 3
四、Clusterin的發現、結構與生物功能 4
第二章 研究方向 7
第三章 材料與方法 8
一、藥品 8
二、酵素 9
三、抗體 10
四、細胞培養液及轉染試劑 10
五、套組試劑 11
六、細胞株 11
七、實驗室提供的質體 12
八、質體的構築 15
九、DNA轉染 15
十、Fas抗體誘導caspase-3活化以及caspase-3 活性測定 15
十一、流式細胞儀分析 16
十二、內切醣酶去醣基反應 16
十三、熱休克誘導CLU mRNA以及蛋白質的表現 16
十四、蛋白質定量 17
十五、正十二烷硫酸鈉-聚丙醯胺板膠電泳 17
十六、西方墨點法 18
十七、萃取RNA 19
十八、反轉錄與聚合酶鏈鎖反應 19
十九、即時聚合酶鏈鎖反應 20
第四章 結果 21
一、HCV非結構性蛋白質NS4A與細胞凋亡之相關性 21
1 NS4A對宿主細胞粒線體膜電位的影響 21
2 NS4A和NS4A突變株對宿主細胞caspase-3活性的影響 22
二、HCV非結構性蛋白質NS4A對宿主細胞內CLU基因表現的影響23
1 HCV非結構性蛋白質對宿主細胞內CLU mRNA的影響 23
2 細胞中CLU蛋白質的特性分析 24
3 NS4A對宿主細胞內及細胞培養液中CLU 蛋白質表現的影響 25
第五章 討論 26
一、NS4A對於細胞內caspase-3活性的影響 26
二、NS4A對宿主細胞CLU基因表現的影響 26
三、NS4A調節宿主細胞caspase-3以及sCLU的可能連結 28
第六章 圖表 29
第七章 參考文獻 45

Agnello, V., Abel, G., Elfahal, M., Knight, G.B. and Zhang, Q.X. (1999) Hepatitis C virus and other flaviviridae viruses enter cells via low density lipoprotein receptor. Proc Natl Acad Sci U S A, 96, 12766-12771.
Araki, S., Israel, S., Leskov, K.S., Criswell, T.L., Beman, M., Klokov, D.Y., Sampalth, L., Reinicke, K.E., Cataldo, E., Mayo, L.D. and Boothman, D.A. (2005) Clusterin proteins: stress-inducible polypeptides with proposed functions in multiple organ dysfunction. BJR Suppl, 27, 106-113.
Bressanelli, S., Tomei, L., Rey, F.A. and De Francesco, R. (2002) Structural analysis of the hepatitis C virus RNA polymerase in complex with ribonucleotides. J Virol, 76, 3482-3492.
Chang, S.C., Cheng, J.C., Kou, Y.H., Kao, C.H., Chiu, C.H., Wu, H.Y. and Chang, M.F. (2000) Roles of the AX(4)GKS and arginine-rich motifs of hepatitis C virus RNA helicase in ATP- and viral RNA-binding activity. J Virol, 74, 9732-9737.
Chang, S.C., Yen, J.H., Kang, H.Y., Jang, M.H. and Chang, M.F. (1994) Nuclear localization signals in the core protein of hepatitis C virus. Biochem Biophys Res Commun, 205, 1284-1290.
Cheng, J.C., Chang, M.F. and Chang, S.C. (1999) Specific interaction between the hepatitis C virus NS5B RNA polymerase and the 3'' end of the viral RNA. J Virol, 73, 7044-7049.
Choo, Q.L., Kuo, G., Weiner, A.J., Overby, L.R., Bradley, D.W. and Houghton, M. (1989) Isolation of a cDNA clone derived from a blood-borne non-A, non-B viral hepatitis genome. Science, 244, 359-362.
Ciccaglione, A.R., Marcantonio, C., Costantino, A., Equestre, M. and Rapicetta, M. (2003) Expression of HCV E1 protein in baculovirus-infected cells: effects on cell viability and apoptosis induction. Intervirology, 46, 121-126.
Ciccaglione, A.R., Marcantonio, C., Tritarelli, E., Equestre, M., Magurano, F., Costantino, A., Nicoletti, L. and Rapicetta, M. (2004) The transmembrane domain of hepatitis C virus E1 glycoprotein induces cell death. Virus Res, 104, 1-9.
Criswell, T., Klokov, D., Beman, M., Lavik, J.P. and Boothman, D.A. (2003) Repression of IR-inducible clusterin expression by the p53 tumor suppressor protein. Cancer Biol Ther, 2, 372-380.
Failla, C., Tomei, L. and De Francesco, R. (1994) Both NS3 and NS4A are required for proteolytic processing of hepatitis C virus nonstructural proteins. J Virol, 68, 3753-3760.
Fink, T.M., Zimmer, M., Tschopp, J., Etienne, J., Jenne, D.E. and Lichter, P. (1993) Human clusterin (CLI) maps to 8p21 in proximity to the lipoprotein lipase (LPL) gene. Genomics, 16, 526-528.
Gong, G., Waris, G., Tanveer, R. and Siddiqui, A. (2001) Human hepatitis C virus NS5A protein alters intracellular calcium levels, induces oxidative stress, and activates STAT-3 and NF-kappa B. Proc Natl Acad Sci U S A, 98, 9599-9604.
Grakoui, A., McCourt, D.W., Wychowski, C., Feinstone, S.M. and Rice, C.M. (1993a) Characterization of the hepatitis C virus-encoded serine proteinase: determination of proteinase-dependent polyprotein cleavage sites. J Virol, 67, 2832-2843.
Grakoui, A., McCourt, D.W., Wychowski, C., Feinstone, S.M. and Rice, C.M. (1993b) A second hepatitis C virus-encoded proteinase. Proc Natl Acad Sci U S A, 90, 10583-10587.
Hijikata, M., Mizushima, H., Akagi, T., Mori, S., Kakiuchi, N., Kato, N., Tanaka, T., Kimura, K. and Shimotohno, K. (1993) Two distinct proteinase activities required for the processing of a putative nonstructural precursor protein of hepatitis C virus. J Virol, 67, 4665-4675.
Humphreys, D.T., Carver, J.A., Easterbrook-Smith, S.B. and Wilson, M.R. (1999) Clusterin has chaperone-like activity similar to that of small heat shock proteins. J Biol Chem, 274, 6875-6881.
July, L.V., Beraldi, E., So, A., Fazli, L., Evans, K., English, J.C. and Gleave, M.E. (2004) Nucleotide-based therapies targeting clusterin chemosensitize human lung adenocarcinoma cells both in vitro and in vivo. Mol Cancer Ther, 3, 223-232.
Kapron, J.T., Hilliard, G.M., Lakins, J.N., Tenniswood, M.P., West, K.A., Carr, S.A. and Crabb, J.W. (1997) Identification and characterization of glycosylation sites in human serum clusterin. Protein Sci, 6, 2120-2133.
Kawai, T., Takahashi, K., Sato, S., Coban, C., Kumar, H., Kato, H., Ishii, K.J., Takeuchi, O. and Akira, S. (2005) IPS-1, an adaptor triggering RIG-I- and Mda5-mediated type I interferon induction. Nat Immunol, 6, 981-988.
Kolykhalov, A.A., Feinstone, S.M. and Rice, C.M. (1996) Identification of a highly conserved sequence element at the 3'' terminus of hepatitis C virus genome RNA. J Virol, 70, 3363-3371.
Kolykhalov, A.A., Mihalik, K., Feinstone, S.M. and Rice, C.M. (2000) Hepatitis C virus-encoded enzymatic activities and conserved RNA elements in the 3'' nontranslated region are essential for virus replication in vivo. J Virol, 74, 2046-2051.
Kou, Y.H., Chang, M.F., Wang, Y.M., Hong, T.M. and Chang, S.C. (2007) Differential requirements of NS4A for the internal NS3 cleavage and polyprotein processing of hepatitis C virus. J Virol.
Kuo, G., Choo, Q.L., Alter, H.J., Gitnick, G.L., Redeker, A.G., Purcell, R.H., Miyamura, T., Dienstag, J.L., Alter, M.J., Stevens, C.E. and et al. (1989) An assay for circulating antibodies to a major etiologic virus of human non-A, non-B hepatitis. Science, 244, 362-364.
Lakins, J., Bennett, S.A., Chen, J.H., Arnold, J.M., Morrissey, C., Wong, P., O''Sullivan, J. and Tenniswood, M. (1998) Clusterin biogenesis is altered during apoptosis in the regressing rat ventral prostate. J Biol Chem, 273, 27887-27895.
Lauer, G.M. and Walker, B.D. (2001) Hepatitis C virus infection. N Engl J Med, 345, 41-52.
Lesburg, C.A., Cable, M.B., Ferrari, E., Hong, Z., Mannarino, A.F. and Weber, P.C. (1999) Crystal structure of the RNA-dependent RNA polymerase from hepatitis C virus reveals a fully encircled active site. Nat Struct Biol, 6, 937-943.
Leskov, K.S., Klokov, D.Y., Li, J., Kinsella, T.J. and Boothman, D.A. (2003) Synthesis and functional analyses of nuclear clusterin, a cell death protein. J Biol Chem, 278, 11590-11600.
Lin, C., Lindenbach, B.D., Pragai, B.M., McCourt, D.W. and Rice, C.M. (1994) Processing in the hepatitis C virus E2-NS2 region: identification of p7 and two distinct E2-specific products with different C termini. J Virol, 68, 5063-5073.
Lin, C., Thomson, J.A. and Rice, C.M. (1995) A central region in the hepatitis C virus NS4A protein allows formation of an active NS3-NS4A serine proteinase complex in vivo and in vitro. J Virol, 69, 4373-4380.
Loison, F., Debure, L., Nizard, P., le Goff, P., Michel, D. and le Drean, Y. (2006) Up-regulation of the clusterin gene after proteotoxic stress: implication of HSF1-HSF2 heterocomplexes. Biochem J, 395, 223-231.
Loo, Y.M., Owen, D.M., Li, K., Erickson, A.K., Johnson, C.L., Fish, P.M., Carney, D.S., Wang, T., Ishida, H., Yoneyama, M., Fujita, T., Saito, T., Lee, W.M., Hagedorn, C.H., Lau, D.T., Weinman, S.A., Lemon, S.M. and Gale, M., Jr. (2006) Viral and therapeutic control of IFN-beta promoter stimulator 1 during hepatitis C virus infection. Proc Natl Acad Sci U S A, 103, 6001-6006.
McLauchlan, J. (2000) Properties of the hepatitis C virus core protein: a structural protein that modulates cellular processes. J Viral Hepat, 7, 2-14.
Meylan, E., Curran, J., Hofmann, K., Moradpour, D., Binder, M., Bartenschlager, R. and Tschopp, J. (2005) Cardif is an adaptor protein in the RIG-I antiviral pathway and is targeted by hepatitis C virus. Nature, 437, 1167-1172.
Michel, D., Chatelain, G., North, S. and Brun, G. (1997) Stress-induced transcription of the clusterin/apoJ gene. Biochem J, 328 ( Pt 1), 45-50.
Miyake, H., Hara, I., Gleave, M.E. and Eto, H. (2004) Protection of androgen-dependent human prostate cancer cells from oxidative stress-induced DNA damage by overexpression of clusterin and its modulation by androgen. Prostate, 61, 318-323.
Miyake, H., Hara, I., Kamidono, S. and Gleave, M.E. (2001) Synergistic chemsensitization and inhibition of tumor growth and metastasis by the antisense oligodeoxynucleotide targeting clusterin gene in a human bladder cancer model. Clin Cancer Res, 7, 4245-4252.
Miyake, H., Nelson, C., Rennie, P.S. and Gleave, M.E. (2000) Testosterone-repressed prostate message-2 is an antiapoptotic gene involved in progression to androgen independence in prostate cancer. Cancer Res, 60, 170-176.
Mizushima, H., Hijikata, M., Asabe, S., Hirota, M., Kimura, K. and Shimotohno, K. (1994) Two hepatitis C virus glycoprotein E2 products with different C termini. J Virol, 68, 6215-6222.
Montpetit, M.L., Lawless, K.R. and Tenniswood, M. (1986) Androgen-repressed messages in the rat ventral prostate. Prostate, 8, 25-36.
Murphy, D.G., Willems, B., Deschenes, M., Hilzenrat, N., Mousseau, R. and Sabbah, S. (2007) Use of sequence analysis of the NS5B region for routine genotyping of hepatitis C virus with reference to C/E1 and 5'' untranslated region sequences. J Clin Microbiol, 45, 1102-1112.
Nomura-Takigawa, Y., Nagano-Fujii, M., Deng, L., Kitazawa, S., Ishido, S., Sada, K. and Hotta, H. (2006) Non-structural protein 4A of Hepatitis C virus accumulates on mitochondria and renders the cells prone to undergoing mitochondria-mediated apoptosis. J Gen Virol, 87, 1935-1945.
Petropoulou, C., Trougakos, I.P., Kolettas, E., Toussaint, O. and Gonos, E.S. (2001) Clusterin/apolipoprotein J is a novel biomarker of cellular senescence that does not affect the proliferative capacity of human diploid fibroblasts. FEBS Lett, 509, 287-297.
Pflugheber, J., Fredericksen, B., Sumpter, R., Jr., Wang, C., Ware, F., Sodora, D.L. and Gale, M., Jr. (2002) Regulation of PKR and IRF-1 during hepatitis C virus RNA replication. Proc Natl Acad Sci U S A, 99, 4650-4655.
Pileri, P., Uematsu, Y., Campagnoli, S., Galli, G., Falugi, F., Petracca, R., Weiner, A.J., Houghton, M., Rosa, D., Grandi, G. and Abrignani, S. (1998) Binding of hepatitis C virus to CD81. Science, 282, 938-941.
Pucci, S., Bonanno, E., Pichiorri, F., Angeloni, C. and Spagnoli, L.G. (2004) Modulation of different clusterin isoforms in human colon tumorigenesis. Oncogene, 23, 2298-2304.
Ruggieri, A., Harada, T., Matsuura, Y. and Miyamura, T. (1997) Sensitization to Fas-mediated apoptosis by hepatitis C virus core protein. Virology, 229, 68-76.
Ruggieri, A., Murdolo, M. and Rapicetta, M. (2003) Induction of FAS ligand expression in a human hepatoblastoma cell line by HCV core protein. Virus Res, 97, 103-110.
Satoh, S., Tanji, Y., Hijikata, M., Kimura, K. and Shimotohno, K. (1995) The N-terminal region of hepatitis C virus nonstructural protein 3 (NS3) is essential for stable complex formation with NS4A. J Virol, 69, 4255-4260.
Scarselli, E., Ansuini, H., Cerino, R., Roccasecca, R.M., Acali, S., Filocamo, G., Traboni, C., Nicosia, A., Cortese, R. and Vitelli, A. (2002) The human scavenger receptor class B type I is a novel candidate receptor for the hepatitis C virus. Embo J, 21, 5017-5025.
Seth, R.B., Sun, L., Ea, C.K. and Chen, Z.J. (2005) Identification and characterization of MAVS, a mitochondrial antiviral signaling protein that activates NF-kappaB and IRF 3. Cell, 122, 669-682.
Shannan, B., Seifert, M., Boothman, D.A., Tilgen, W. and Reichrath, J. (2006) Clusterin and DNA repair: a new function in cancer for a key player in apoptosis and cell cycle control. J Mol Histol, 37, 183-188.
Siavoshian, S., Abraham, J.D., Thumann, C., Kieny, M.P. and Schuster, C. (2005) Hepatitis C virus core, NS3, NS5A, NS5B proteins induce apoptosis in mature dendritic cells. J Med Virol, 75, 402-411.
Sumpter, R., Jr., Loo, Y.M., Foy, E., Li, K., Yoneyama, M., Fujita, T., Lemon, S.M. and Gale, M., Jr. (2005) Regulating intracellular antiviral defense and permissiveness to hepatitis C virus RNA replication through a cellular RNA helicase, RIG-I. J Virol, 79, 2689-2699.
Tai, C.L., Chi, W.K., Chen, D.S. and Hwang, L.H. (1996) The helicase activity associated with hepatitis C virus nonstructural protein 3 (NS3). J Virol, 70, 8477-8484.
Tanaka, T., Kato, N., Cho, M.J. and Shimotohno, K. (1995) A novel sequence found at the 3'' terminus of hepatitis C virus genome. Biochem Biophys Res Commun, 215, 744-749.
Tanaka, T., Kato, N., Cho, M.J., Sugiyama, K. and Shimotohno, K. (1996) Structure of the 3'' terminus of the hepatitis C virus genome. J Virol, 70, 3307-3312.
Tardif, K.D., Mori, K. and Siddiqui, A. (2002) Hepatitis C virus subgenomic replicons induce endoplasmic reticulum stress activating an intracellular signaling pathway. J Virol, 76, 7453-7459.
Trougakos, I.P. and Gonos, E.S. (2002) Clusterin/apolipoprotein J in human aging and cancer. Int J Biochem Cell Biol, 34, 1430-1448.
Trougakos, I.P., So, A., Jansen, B., Gleave, M.E. and Gonos, E.S. (2004) Silencing expression of the clusterin/apolipoprotein j gene in human cancer cells using small interfering RNA induces spontaneous apoptosis, reduced growth ability, and cell sensitization to genotoxic and oxidative stress. Cancer Res, 64, 1834-1842.
VanWeelden, K., Flanagan, L., Binderup, L., Tenniswood, M. and Welsh, J. (1998) Apoptotic regression of MCF-7 xenografts in nude mice treated with the vitamin D3 analog, EB1089. Endocrinology, 139, 2102-2110.
Wang, C., Sarnow, P. and Siddiqui, A. (1993) Translation of human hepatitis C virus RNA in cultured cells is mediated by an internal ribosome-binding mechanism. J Virol, 67, 3338-3344.
Yang, C.R., Yeh, S., Leskov, K., Odegaard, E., Hsu, H.L., Chang, C., Kinsella, T.J., Chen, D.J. and Boothman, D.A. (1999) Isolation of Ku70-binding proteins (KUBs). Nucleic Acids Res, 27, 2165-2174.
Yang, S.H., Lee, C.G., Song, M.K. and Sung, Y.C. (2000) Internal cleavage of hepatitis C virus NS3 protein is dependent on the activity of NS34A protease. Virology, 268, 132-140.
Yao, N., Reichert, P., Taremi, S.S., Prosise, W.W. and Weber, P.C. (1999) Molecular views of viral polyprotein processing revealed by the crystal structure of the hepatitis C virus bifunctional protease-helicase. Structure, 7, 1353-1363.
Yoneyama, M., Kikuchi, M., Natsukawa, T., Shinobu, N., Imaizumi, T., Miyagishi, M., Taira, K., Akira, S. and Fujita, T. (2004) The RNA helicase RIG-I has an essential function in double-stranded RNA-induced innate antiviral responses. Nat Immunol, 5, 730-737.
Zellweger, T., Chi, K., Miyake, H., Adomat, H., Kiyama, S., Skov, K. and Gleave, M.E. (2002) Enhanced radiation sensitivity in prostate cancer by inhibition of the cell survival protein clusterin. Clin Cancer Res, 8, 3276-3284.
Zhang, H., Kim, J.K., Edwards, C.A., Xu, Z., Taichman, R. and Wang, C.Y. (2005) Clusterin inhibits apoptosis by interacting with activated Bax. Nat Cell Biol, 7, 909-915.
Zhu, N., Ware, C.F. and Lai, M.M. (2001) Hepatitis C virus core protein enhances FADD-mediated apoptosis and suppresses TRADD signaling of tumor necrosis factor receptor. Virology, 283, 178-187.