All issues
Volume 55 (2005)
- Issue 2 Pages 207-
- Issue 1 Pages 1-
Predecessor
Volume 55, Issue 2
Displaying 1-14 of 14 articles from this issue
- |<
- <
- 1
- >
- >|
Reviews
-
Masato TSURUDOME2005 Volume 55 Issue 2 Pages 207-219
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSThe majority of viral fusion proteins can be divided into two classes. The influenza hemagglutinin (HA) belongs to the class I fusion proteins and undergoes a series of conformational changes at acidic pH, leading to membrane fusion. The crystal structures of the prefusion and the postfusion forms of HA have been revealed in 1981 and 1994, respectively. On the basis of these structures, a model for the mechanism of membrane fusion mediated by the conformational changes of HA has been proposed. The flavivirus E and alphavirus E1 proteins belong to the class II fusion proteins and mediate membrane fusion at acidic pH. Their prefusion structures are distinct from that of HA. Last year, however, it has become evident that the postfusion structures of these class I and class II fusion proteins are similar. The paramyxovirus F protein belongs to the class I fusion proteins. In contrast to HA, an interaction between F and its homologous attachment protein is required for F to undergo the conformational changes. Since F mediates fusion at neutral pH, the infected cells can fuse with neighboring uninfected cells. The crystal structures of F and the attachment protein HN have recently been clarified, which will facilitate studies of the molecular mechanism of F-mediated membrane fusion.View full abstractDownload PDF (336K) -
Hironori SATO, Masaru YOKOYAMA2005 Volume 55 Issue 2 Pages 221-229
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSActively replicating RNA viruses in nature are continually changing their genetic information by spontaneous mutations. These changes often result in alterations in immune-sensitivity, drug-sensitivity, cell-tropism, and host-range, causing uncontrollability of the pathogen and emerging/re-emerging infections. To better understand the virus changes and develop effective methods to control the moving targets, it is essential to obtain information on changes in viral genomes and proteins. Although information on genetic changes is being accumulated very rapidly, assessment of changes in protein structure and function still requires time-consuming works. In this review, we will overview mutation studies of human immunodeficiency virus and other RNA viruses. In addition, we will introduce recent advances in the computational science and its application on mutation studies and drug development.View full abstractDownload PDF (328K) -
Masaji MASE, Yoshihiro KAWAOKA2005 Volume 55 Issue 2 Pages 231-237
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSCurrently, H5N1 influenza viruses remain a serious public health concern in Asia and now in Europe. We showed that the H5N1 viruses associated with outbreaks of HPAI in chickens in Japan were genotypically closely related to an H5N1 virus isolated from a chicken in China in 2003 (genotype V), but were different from those prevalent in southeastern Asia in 2003-2004 (i.e., genotype Z). H5N1 viruses were also isolated from duck meat imported from China during this routine surveillance in May of 2003. We characterized these H5N1 isolates and found that poultry products contaminated with influenza viruses of high pathogenic potential to mammals are a threat to public health even in countries where the virus is not enzootic and represent a possible source of influenza outbreaks in poultry.View full abstractDownload PDF (215K) -
Therapeutic inhibition of Epstein-Barr virus-associated tumor cell growth by dominant-negative EBNA1Shosuke IMAI, Masayuki KURODA, Ryusuke YAMASHITA, Yoshihito ISHIURA2005 Volume 55 Issue 2 Pages 239-249
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSEpstein-Barr virus (EBV) nuclear antigen 1 (EBNA1), a latent viral protein consistently expressed in infected proliferating cells, is essentially required in trans to maintain EBV episomes in cells. Thus EBNA1 will be an appropriate target for specific molecular therapy against EBV-associated cancers. We constructed a mutant (mt) EBNA1 lacking the N-terminal-half, relative to wild-type (wt) EBNA1, and demonstrated that it exerted dominant-negative effects on maintenance of the viral episome from cells regardless of viral latency or tissue origin thereby leading to significant suppression of naturally EBV-harboring Burkitt's lymphoma cell growth in vitro and in vivo. Our mutant can act as dominant-negative (dn) EBNA1 and will afford an additional therapeutic strategy specifically targeting EBV-associated malignancies. The similar approach can be applicable to exploit novel remedial protocols against uncontrollable diseases caused by other persistently-infected viruses. In addition, dnEBNA1 may also provide a useful analytical tool for the possible oncogenic function(s) of wtEBNA1.View full abstractDownload PDF (382K)
Special Issue
-
Yoshio KOYANAGI2005 Volume 55 Issue 2 Pages 251-257
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSA number of novel findings with reference to HIV replication have been reported even though it passed more than 20 years after a first HIV isolation. Although many cellular factors are known to be involved in the HIV replication, recently investigators discovered novel HIV-suppressive cellular factors such as APOBEC or TRIM5α. Here, I describe and discuss how HIV uses the cellular machinery for its replication.View full abstractDownload PDF (358K) -
Emi E. NAKAYAMA, Tatsuo SHIODA2005 Volume 55 Issue 2 Pages 259-265
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSHuman immunodeficiency virus type 1 (HIV-1) shows a very narrow host range limited only to humans and chimpanzees. HIV-1 dose not experimentally infect Old World monkeys, such as rhesus and cynomolgus monkeys, and fails to replicate in activated CD4 positive T lymphocytes obtained from those monkeys. Several lines of evidence have suggested that the block of HIV-1 replication in Old World monkey cells occured at a post-entry step and appeared to result from a failure to initiate reverse transcription.
Recently, the screening of a rhesus monkey cDNA library identified tripartite motif 5 (TRIM5) α, a component of cytoplasmic bodies, as a factor that confers resistance to HIV-1 infection. Shortly after, TRIM5α of African green monkey, another Old World monkey, was also shown to restrict HIV-1 infection, while human TRIM5α was reported to restrict N-tropic murine leukemia virus. Small amino acid differences in the SPRY domain among human and monkey TRIM5αs were reported to determine species-specific restriction. This review discusses about anti-viral activity of TRIM5α.View full abstractDownload PDF (334K) -
Akifumi TAKAORI2005 Volume 55 Issue 2 Pages 267-272
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSAPOBEC3G is a potent antiretroviral factor, which belongs to the APOBEC superfamily of cytidine deaminases. It deaminates cytidine to uridine in nascent minus-strand viral DNA, inducing G-to-A hypermutation in the plus-strand viral DNA. HIV-1 Vif protein overcomes the antiviral activity of APOBEC3G by targeting it for ubiquitin-dependent degradation. Recent accumulating evidences that other members of APOBEC proteins also show antiviral activity on a wide variety of viruses suggest that APOBEC family proteins play a crucial role in an antiviral defense as an innate immunity. Here, we review recent progress in research on APOBEC3 proteins.View full abstractDownload PDF (292K) -
Shogo MISUMI2005 Volume 55 Issue 2 Pages 273-279
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSIt is well-known that a peptidyl-prolyl cis-trans isomerase cyclophilin A (CyPA) is incorporated into Human immunodeficiency virus type 1 (HIV-1) particle. The proteome analysis of the purified HIV-1 strain LAV-1 (HIV-1LAV-1) reveals that three isoforms of CyPA with an isoelectric point (pI) of 6.00, 6.40, and 6.53 are inside the viral membrane and another isoform with a pI of 6.88 is outside the viral membrane; and that the CyPA isoform with a pI of 6.53 is N-acetylated. The mechanisms that permit the redistribution of CyPA with a pI of 6.88 on the viral surface have not yet been clarified, but it penetrates the viral membrane after budding.View full abstractDownload PDF (240K) -
Jiro YASUDA2005 Volume 55 Issue 2 Pages 281-286
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSHIV, as well as many enveloped viruses, exits the cells by budding directly from the plasma membrane. HIV budding is dependent on a PTAP motif, which is located within the p6 domain of Gag. Recent studies have shown that the cellular protein Tsg101 binds to the PTAP L-domain motif of HIV p6 and facilitates the final stages of virus release.
Tsg101 function in the cellular vacuolar protein sorting pathway, where they play central roles in selecting cargo for incorporation into vesicles that bud into the maturing endosome to create multivesicular bodies (MVBs). Vesicle budding into the MVB and viral budding at the plasma membrane are topologically equivalent, and the same machinery could catalyze both processes. It will be important to understand the mechanism of virus budding in detail, since virus budding may be a potential target for interference with HIV propagation.View full abstractDownload PDF (211K)
Topics
-
Takanobu KATO, Takaji WAKITA2005 Volume 55 Issue 2 Pages 287-295
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSHepatitis C virus (HCV) is a major public health problem, infecting an estimated 170 million people worldwide. Current therapy for HCV-related chronic hepatitis is based on the use of interferon. However, virus clearance rates are insufficient. Investigations to develop the anti-viral therapy or to understand the life cycle of this virus have been hampered by the lack of viral culture systems. We isolated the JFH-1 strain from a patient with fulminant hepatitis, and the JFH-1 subgenomic replicon could replicate efficiently in culture cell without adaptive mutation. Recently, we developed the HCV infection system in culture cells with this JFH-1 strain. The full-length JFH-1 RNA was transfected into Huh7 cells. Subsequently, viral RNA efficiently replicated in transfected cells and viral particles were secreted. Furthermore, secreted virus displayed infectivity for naive Huh7 cells. This system provides a powerful tool for studying the viral life cycle and constructing anti-viral strategies.View full abstractDownload PDF (278K) -
Koki TANIGUCHI, Mitsutaka WAKUDA2005 Volume 55 Issue 2 Pages 297-302
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSPicobirnavirus is named after the small birnavirus which contains two double-stranded RNA segments as a genome. However, their properties are quite different to each other. Although the virus has been detected mainly from the stools of gastroenteritis patients and several mammals and birds, the pathogenicity of the virus has not been established. Characterizations of the virus are hampered due to the lack in the system for multiplication of the virus in cultured cells or experimental animals. Recently, complete nucleotide sequences of two RNA segments of a human picobirnavirus detected in Thailand were determined.View full abstractDownload PDF (189K) -
Nobuhiko OKABE2005 Volume 55 Issue 2 Pages 303-306
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSIn Japan, more than 5,000 patients were reported in 1950, and there have been less than 10 cases annually since 1992. However, Japanese encephalitis virus caused of Japanese encephalitis (JE) are still existed highly and widely in the country, reported by National Institute of Infectious Diseases with serological examination among domestic pig population. JE immunization had been provided to children as category 1 routine immunization in Japan. However, the Ministry of Health, Labor and Welfare (HOHLW) decided not to recommend JE immunization to children as a routine immunization at May 2005. Major reason on this decision was that the Minter of MOHLW certified to pay loss of medical costs for the case of ADEM (acute disseminated encephalomyelopathy) after JE immunization, recognized as adverse events with JE vaccine, although MOHLW stated that the strict scientific evidence was unknown. MOHLW stated also that it is expected Vero cell derived JE vaccine should be replaced with the present mouse brain derived JE vaccine as the next generation, to be able to avoid theoretical possibility of neurological adverse events associated with JE vaccine. Small but increasing number of requests recently to be certified as health injuries on ADEM cases associated with JE immunization is also another reason for MOHLLW`s decision. Further, fifth doses of JE vaccine given to children at 14-15 years old as a routine immunization was decided to be discontinued by MOHLW at July 2005, considering present epidemiological situation on JE and JE immunization status in Japan, although four doses has been recommended continuously as routine. The background details on JE vaccine issues decided by MOHLW in 2005 were reviewed on this paper.View full abstractDownload PDF (196K) -
Ichiro KURANE2005 Volume 55 Issue 2 Pages 307-312
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSJapanese encephalitis (JE) is a serious encephalitis caused by JE virus. Approximately 20% of JE patients die and 50% patients recover with neuro-psychiatric sequelae. In Japan, the number of JE patients was over 1000 per year in 1960s; however, the number decreased dramatically and has been less than 10 since 1990. Ministry of Health, Labour and Welfare suspended the strong recommendation for vaccination with the mouse brain-derived JE vaccine, because of cases who developed acute disseminated encephalomyelitis (ADEM) after vaccination with JE vaccine. However, it has not been fully confirmed on scientific bases that ADEM was caused by mouse brain-derived JE vaccine. Tissue culture derived-JE vaccine is under development. It is expected that this new vaccine will come to the market soon and that the recommendation of universal vaccination with JE vaccine will be implemented at the earliest occasion.View full abstractDownload PDF (290K)
Original Report
-
Subaru OGISO, Junsuke SHIRAI, Yoshinori TUCHIYA, Eiichi HONDA2005 Volume 55 Issue 2 Pages 317-326
Published: 2005
Released on J-STAGE: March 23, 2006
JOURNAL FREE ACCESSAntiviral assay is used routinely for measuring the biological activity of interferon (IFN). However, the challenge viruses used in these assays are considered dangerous to the animal industry and pose a risk of human infection. For example, the vesicular stomatitis virus (VSV) is an important exotic disease agent in domestic animals, and the sindbis virus provokes rash, arthralgia, and fever in humans. Therefore, biosafety needs to be considered when antiviral assays are performed. We chose Getah virus as a candidate challenge virus because it is less hazardous to animals and humans. Crystal violet staining 50% CPE inhibition antiviral assay of human IFN using Getah virus was studied. Antiviral assay using Getah virus and FL cells gave a higher titer of human IFN than did assay using VSV. The titer of human IFNαwas almost the same as that given by standardized control samples. The titer of human IFN by antiviral assay using Getah virus on the sheet method (IFN reacted the sheeted FL cells) was higher than those of the simultaneous reaction method (IFN reacted the suspending FL cells before sheeted). We therefore consider the sheet method useful for detection of small amounts of IFN. Antiviral assay using Getah virus on MDBK cells gave a lower titer of human IFNα than did assay using VSV. However, the adjusting the number of MDBK cells and the titer of Getah virus to get the best condition for CPE appearance, gave similar results in the assays using Getah virus and VSV. We consider that Getah virus is a potentially useful challenge virus for antiviral assay of human IFN.View full abstractDownload PDF (831K)
- |<
- <
- 1
- >
- >|