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Analysis of retinoblastoma for human adenovirus and human JC virus genome integration.

Human adenovirus groups A and B have an oncogenic potential in newborn rodents. Especially, adenovirus type 12 is known to induce retinoblastoma-like tumor in baboons and transform human embryo retinoblast cells in vitro. Human JC virus is also known to produce a variety of tumors in newborn rodents, including retinoblastoma-like tumor. In this experiment, cell DNAs of human retinoblastomas were assayed for each of the transforming gene sequences of adenovirus groups A, B, C, D and E and for JC virus gene sequences, by using Southern blot hybridization. None of these viral gene sequences were detected at the level of 0.1-0.5 copy per diploid cell DNA in all of 11 retinoblastomas, including 6 retinoblastomas previously examined for adenovirus 12-transforming gene sequences. This led to a conclusion that most, if not all, adenoviruses and JC virus play no essential role in the etiology of human retinoblastoma, although there were experimental models of retinoblastoma induced by these viruses.

Adenoviruses, Human↗

Molecular detection of JC virus in embalmed, formalin-fixed, paraffin-embedded brain tissue.

Embalmed tissues are adequate for the detection of JC virus in lesions of progressive multifocal leukoencephalopathy (PML) by immunohistologic and molecular methods. JC virus was readily detected in embalmed brain tissue using immunohistochemistry (IHC), in situ hybridization (ISH), and the polymerase chain reaction (PCR). Two brains were removed from bodies that had been embalmed at least 24 h prior to autopsy. They were subsequently post fixed in 10% buffered formalin for 10-14 days before dissection and molecular studies were performed. Though these techniques are not novel, their use in embalmed tissues is. Routine embalming should not eliminate these diagnostic procedures from consideration.

Brain↗

Identification of critical elements within the JC virus DNA replication origin.

The T antigen of JC virus (JCV) does not interact productively with the simian virus 40 (SV40) origin of replication. In contrast, the SV40 T antigen does drive replication from the JCV origin as well as from its own. The basis for this restricted interaction was investigated by analyzing the structure of the JCV replication origin. The replication activities of JCV-SV40 hybrid origin plasmids were tested in cells constitutively producing either the JCV or SV40 T antigen. Results indicated that a region of the JCV origin critical for interaction with the JCV T antigen was positioned to the late side of the central palindrome of the putative core origin. A mutational analysis of this region indicated that the sequence of the A + T-rich tract was primarily responsible for determining the efficiency with which JCV can initiate replication from its origin. The tandemly repeated pentameric sequence AGGGA located proximal to the A + T-rich tract in the JCV enhancer element was found to stimulate JCV, but not SV40, T antigen-mediated replication. The effect on replication of other elements within the JCV enhancer was also dependent on the T antigen employed for initiation. A plasmid containing the replication origin of prototype BK virus was unable to replicate in cells containing JCV T antigen, again indicating the inflexibility of the JCV T antigen in interacting with heterologous origins.

Animals↗

The major capsid protein, VP1, of human JC virus expressed in Escherichia coli is able to self-assemble into a capsid-like particle and deliver exogenous DNA into human kidney cells.

The full-length major capsid protein, VP1, of the human polyomavirus JC virus was cloned and expressed in Escherichia coli. VP1 protein expressed in E. coli self-assembled into capsid-like particles and caused haemagglutination of human O-type red blood cells. Caesium chloride density-gradient centrifugation analysis revealed that the capsid-like particles consisted of virion-like pseudovirion and empty capsid-like pseudocapsid populations. The morphology of pseudo-virion and pseudocapsid particles was observed under the electron microscope. The pseudovirions contained DNA and RNA molecules but the pseudocapsids did not contain any nucleic acid, as analysed by DNA extraction. DNA-binding activity of VP1 was also demonstrated by the South-Western probing method in vitro. Furthermore, pseudocapsids were able to deliver exogenous DNA into human foetal kidney epithelial cells. These results indicate that recombinant JC virus VP1 is able to self-assemble into capsid-like particles and to package DNA in the absence of the minor capsid proteins, VP2 and VP3. This prokaryotic assembly system may facilitate the investigation of maturation mechanism(s) of polyomaviruses. Furthermore, capsid-like particles of JC virus VP1 generated in E. coli potentially could be used as a human gene transfer vector.

Capsid↗

Induction of undifferentiated brain tumors in rats by a human polyomavirus (JC virus).

Newborn SD rats were inoculated intracranially with JC virus (Tokyo-1), a human polyomavirus, isolated from the autopsied brain of a patient with progressive multifocal leukoencephalopathy. Twenty-one to 61 weeks later, 20 of 27 rats developed tumors in the cerebrum, but not in the cerebellum. The undifferentiated neuroectodermal nature of the tumors was histologically, immunohistochemically and ultrastructurally confirmed.

Animals↗

Increased p53 immunopositivity in anaplastic medulloblastoma and supratentorial PNET is not caused by JC virus.

BACKGROUND: p53 mutations are relatively uncommon in medulloblastoma, but abnormalities in this cell cycle pathway have been associated with anaplasia and worse clinical outcomes. We correlated p53 protein expression with pathological subtype and clinical outcome in 75 embryonal brain tumors. The presence of JC virus, which results in p53 protein accumulation, was also examined. METHODS: p53 protein levels were evaluated semi-quantitatively in 64 medulloblastomas, 3 atypical teratoid rhabdoid tumors (ATRT), and 8 supratentorial primitive neuroectodermal tumors (sPNET) using immunohistochemistry. JC viral sequences were analyzed in DNA extracted from 33 frozen medulloblastoma and PNET samples using quantitative polymerase chain reaction. RESULTS: p53 expression was detected in 18% of non-anaplastic medulloblastomas, 45% of anaplastic medulloblastomas, 67% of ATRT, and 88% of sPNET. The increased p53 immunoreactivity in anaplastic medulloblastoma, ATRT, and sPNET was statistically significant. Log rank analysis of clinical outcome revealed significantly shorter survival in patients with p53 immunopositive embryonal tumors. No JC virus was identified in the embryonal brain tumor samples, while an endogenous human retrovirus (ERV-3) was readily detected. CONCLUSION: Immunoreactivity for p53 protein is more common in anaplastic medulloblastomas, ATRT and sPNET than in non-anaplastic tumors, and is associated with worse clinical outcomes. However, JC virus infection is not responsible for increased levels of p53 protein.

Adolescent↗

Genotypes of JC virus, DNA of cytomegalovirus, and proviral DNA of human immunodeficiency virus in eyes of acquired immunodeficiency syndrome patients.

JC virus (JCV) is a human polyomavirus that exists in at least eight different genotypes as a result of coevolution with different human populations all over the world. Well adapted to its host, it usually persists in the kidneys and possibly the brain. If the host becomes immunodeficient, JCV can cause the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML). There is increasing evidence that JCV is transactivated by cytomegalovirus (CMV) and the human immunodeficiency virus (HIV). Both CMV and HIV can infect the retina of acquired immunodeficiency syndrome (AIDS) patients, causing severe necrosis in the case of CMV retinitis or a mild HIV-associated vasculopathy, with bleeding and cotton wool spots. The authors therefore investigated by polymerase chain reaction (PCR) whether DNA of these three viruses was detectable in paraffin-embedded eyes of AIDS patients with a clinical history of CMV retinitis. From a total of 65 eyes, JCV was detected in 21 (32%). Thirty-six (55%) were positive for CMV and 6 (9%) for proviral DNA of HIV. JCV and CMV were found in 13 eyes, JCV and HIV in 3 eyes, CMV and HIV in 1 eye, and DNA from all three viruses in 1 eye. The JCV genotypes were types 1A, 2A, 2E, 3, and 4. In 21 eyes of patients without AIDS, only one sample was JCV positive. In conclusion, JCV DNA can be detected in ocular tissue of AIDS patients at a significantly higher level than in eyes of nonimmunosuppressed patients. Further investigations will help to decide if JCV contributes to the retinopathy caused by CMV and HIV.

Acquired Immunodeficiency Syndrome↗

Progressive multifocal leukoencephalopathy with detection of JC virus in a patient with chronic lymphocytic leukemia parallel to onset of fludarabine therapy.

Along with the establishment of more intense chemotherapeutic regimens including fludarabine for the treatment of indolent lymphoproliferative diseases like chronic lymphocytic leukemia (CLL), an increasing amount of cases with progressive multifocal leukoencephalopathy (PML) due to JC virus have been observed. We report a patient with CLL who developed PML parallel to the onset of fludarabine therapy. Spinal fluid was tested positive for JC virus. Despite virostatic treatment with cidofovir, neurologic symptoms were progressive and the disease ultimately fatal. The present case suggests that immunosuppression caused by chronic lymphoproliferative malignancies alone may be a factor in the development of PML. Chemotherapy with fludarabine may act as an additional trigger. The question remains whether serologic screening for JC virus in patients with chronic lymphoproliferative disease undergoing intense chemotherapy might be valuable once sufficient antiviral treatment has been established.

Antineoplastic Agents↗

Self-assembly of the JC virus major capsid protein, VP1, expressed in insect cells.

The major capsid protein of human polyomavirus JC virus, VP1, has been cloned into a baculovirus genome and expressed in insect cells. The VP1 protein was expressed in the cytoplasm and transported into the nucleus. It was then purified by a sucrose cushion and CsCI density gradient centrifugation to near homogeneity. Electron microscopy showed that isolated recombinant VP1 protein self-assembled into a capsid-like structure similar to the natural empty capsid. Both chelator (EDTA) and reducing agent (DTT) are required to disrupt the capsid structure into the pentameric capsomeres, as demonstrated by haemagglutination assay and electron microscopy. These results suggest that JC virus VP1 can be transported into the nucleus and self-assembled to form capsid-like particles without the involvement of the viral minor capsid proteins, VP2 and VP3. In addition, metal ions and disulphide bonds appear to be important in maintaining the integrity of the viral capsid structure.

Amino Acid Sequence↗

NFAT4 is required for JC virus infection of glial cells.

The human polyomavirus JC virus (JCV) infects 70% of the population worldwide. In immunosuppressed patients, JCV infection can lead to progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disease of the central nervous system (CNS). The majority of PML cases occur in the setting of human immunodeficiency virus (HIV) infection, and it has been suggested that the link between HIV and the development of PML is in part related to the production of numerous cytokines in the CNS during HIV infection. To examine the link between the expression of inflammatory cytokines and JCV infection, we tested an anti-inflammatory compound, cyclosporine A (CsA), for its ability to block JCV infection of glial cells. We found that CsA inhibited JCV infection by preventing the activation of the transcription factor nuclear factor of activated T cells 4 (NFAT4). Luciferase reporter assays and chromatin immunoprecipitation assays revealed that NFAT4 directly bound the JCV promoter during infection and was important for the activation of both early and late transcription. In addition, the expression of the JCV early viral gene products increased NFAT activity to further aid viral transcription. The necessity of NFAT for JCV infection suggests that calcium signaling and the activation of NFAT in glial cells are required for JCV infection of the CNS.

Amino Acid Sequence↗

Asian domains of four major genotypes of JC virus, Af2, B1-b, CY and SC.

JC virus (JCV) strains worldwide can be classified into various genotypes based on DNA sequence variations. To define the domains of the four major JCV genotypes in Asia, we collected urine samples at six unstudied sites: three in southeastern Asia, two in the central highlands and one in central Asia. DNA was extracted from urine samples, and used to amplify a 610-bp region of the viral genome. For each geographical site, we determined 16 to 31 sequences, from which a phylogenetic tree was constructed to unambiguously classify detected JCV isolates into distinct genotypes. From JCV genotype profiles at the sites studied here and elsewhere, the following conclusions were drawn. Although Af2 is the major genotype in Africa, this genotype also occurs in western and central Asia. B1-b mainly occurs in western and central Asia, including the central highlands. CY occurs in northeastern Asia with the southern boundary between China and southeast Asian countries. Although SC predominates in southeastern Asia, it also occurs in northern and central Asia at lower frequencies. In addition, a few minor JCV genotypes (B1-a, B2 and B3) occur at many sites. We discuss here the anthropological and medical significance of the present findings.

Adult↗

Molecular analysis of JC virus genotypes circulating among the Italian healthy population.

JC virus (JCV) is an unique virus, but eight different JCV genotypes and various subtypes have been individuated, with a geographic distribution that has been described in general but still needs to be detailed. To define JCV genotype epidemiology in Italy, the authors collected urine from 211 healthy individuals living in Northern, Central, and Southern Continental Italy, and in the two main Italian islands. As screening, JCV DNA was searched using a polymerase chain reaction (PCR) designed to amplify the highly conserved large T (LT) antigen-coding region. Then, to define JCV genotype and trascriptional control region (TCR) organization, fragments of major capsid protein (VP1) and TCR region were amplified and subjected to nucleotide sequencing. The mean frequency of JCV viruria was of 46%, without differences among the four geographically divided groups and between females and males. JCV types 1 and 4 were the most frequently detected, whereas JCV type 2 was rare, and type 3 was found only in one subject. The low frequency of JCV type 2 contrasts with the reported high frequency of this subtype in progressive multifocal leukoencephalopathy (PML), and supports its specific role in PML. The data indicate that JCV genotype epidemiology in Italy is quite different from that of other European countries; moreover, differences between the various Italian regions have been observed. An unexpected high frequency of a new variant of JCV type 4 with a stable point mutation (C --> G) at nucleotide 1851 was found. Furthermore, all the urinary strains had a TCR showing an archetypal organization.

Adult↗

Detection of JC virus DNA sequences in colorectal cancers in Japan.

JC virus (JCV), a ubiquitous polyoma virus that commonly infects humans, was first identified as the etiologic agent for the fetal demyelinating disease, progressive multifocal leukoencephalopathy. Recently, a number of reports have documented detection of JCV in samples derived from several types of neural as well as non-neural human tumors. It has been suggested that oncogenicity of JCV depends on a T antigen having a strict structural homology to the T antigen of simian virus 40. To clarify whether JCV might have a potential role with regard to colorectal cancers, we investigated the presence of its genome in a series of cases along with colorectal adenomas and normal colonic mucosa, targeting T antigen, VP and agnoprotein by nested polymerase chain reaction and Southern blotting and T antigen by immunohistochemistry. While VP and agnoprotein were not found in any of the samples examined, T antigen was detected in 6 of 23 colorectal cancers (26.1%) and 1 of 21 adenomas (4.8%), but none of 20 samples of normal colonic mucosa. No clear and diffuse staining with anti-T-antigen antibodies (1:100) could be detected, and there was no correlation with CD20-positive cells, which might have indicated JCV latent infection of B lymphocytes. Presence of T antigen did not influence clinicopathological variables, including survival. In one colonic cancer case positive for T antigen together with lymph node metastasis, DNA extracted from cancer cells in the lymph node revealed no detection of T antigen. Our results are in the intermediate position between the high T antigen rate (81%) in one report and the lack of it (0%) in another focused on colon cancers. It was concluded that T antigen might be integrated in cancer cells in approximately one fourth of Japanese colon cancer cases without clear and diffuse expression of the protein, suggesting a possible role in oncogenesis which might involve a hit-and-run mechanism.

Adenocarcinoma↗

Production of the antigen and the antibody of the JC virus major capsid protein VP1.

The DNA of the major capsid protein VP1 of the human polyomavirus JC virus (JCV), Taiwan-3 strain, was generated from the urine of an autoimmune disease patient by polymerase chain reaction (PRC). The VP1 DNA was cloned into a prokaryotic expression vector, pGEX-4T-1, for expression in E. coli. The nucleotide sequences and the deduced amino acid sequences were determined and compared with the JC virus prototype, Mad-1. Thirty nucleotides were different between these two strains. Six of the altered nucleotides affected amino acid coding and ten of them caused changes in endonuclease recognition sites. The recombinant VPI protein was purified and used to raise monospecific antiserum in rabbit. Recombinant JCV VP1 protein and its monospecific antiserum are important clinical reagents and could possibly be developed as a subunit vaccine and as a serological diagnostic antigen in the future. In addition, the region between amino acid residues 40 and 80 of JCV VP1 is predicted to be an antigenic epitope on the basis of its hydropathy plot and comparison with the VP1 sequences of SV40 and BK virus.

Amino Acid Sequence↗

Induction of peripheral neuroblastomas in Syrian hamsters after injection as neonates with JC virus, a human polyoma virus.

Neuroblastomas developed in 10 of 31 Syrian hamsters inoculated intraocularly with JC virus, a human polyoma virus. The latent period was 6 to 11 months. Primary tumors occurred in the abdominal cavity, pelvis, mediastinum, and neck region. The origin of one tumor from the adrenal gland was demonstrated. Metastases were seen in the liver, bone marrow, and lymph nodes. Two neuroblastomas arising in this experiment were transplanted serially in weanling hamsters, and a tissue culture cell line was established from one of the transplanted tumors. T-antigen was detected in three of five primary tumors tested and in the transplanted tumors. Antibody against T-antigen was demonstrated in sera from five of six animals with neuroblastomas. Neuroblastomas also developed after combined s.c. and i.p. injection of JC virus.

Animals↗

Nucleotide sequence of the region encompassing the JC virus origin of DNA replication.

The region of the JC virus (JCV) genome from 0.58 to 0.73 map units was sequenced by the Maxam-Gilbert technique. This segment of DNA specifies several regulatory elements and the amino-terminal portion of the early viral proteins. Comparisons with the analogous regions in the polyomaviruses simian virus 40 (SV40) and BK virus (BKV) confirm the close evolutionary relationship of these three viruses. Similarities include palindromic and symmetrical sequences near their origins of DNA replication, binding sites for their large T proteins, an AT-rich region (the Goldberg-Hogness, or TATA, box), and a large tandem duplication or triplication to the late side of their replication origins (however, these sequences differ). Homology between the sequences coding for the early proteins is also evident (79 and 93 of the first 110 amino acids are shared with SV40 and BKV, respectively). Of greater interest are features of the JCV genome which differ from those of other polyomaviruses. Absent in JCV and BKV are sequences which resemble the third T-antigen binding site of SV40. In addition, a set of sequences present in JCV and BKV DNAs (33 nucleotides in JCV and 22 nucleotides in BKV) and located near a 17-base-pair palindrome shared by all three viruses is missing in SV40 DNA. Another sequence, GGGXGGAG, which is repeated several times in many polyomaviruses and adenoviruses and which is thought to play a role in DNA replication or transcription or both, is not found near the JCV origin of replication. Finally, the tandem repeat of JCV, unlike those of BKV and SV40, includes the Goldberg-Hogness sequence.

Amino Acid Sequence↗

Genomic structure of human polyoma virus JC: nucleotide sequence of the region containing replication origin and small-T-antigen gene.

The nucleotide sequence of the region of human polyoma virus JC DNA between 0.5 and 0.7 map units from a unique EcoRI cleavage site was determined and compared with those of the corresponding regions of another human polyoma virus, BK, and simian virus 40 DNAs. Within this region consisting of 945 base pairs, we located the origin of DNA replication near 0.7 map units, the entire coding region for small T antigen, and the splice junctions for large-T-antigen mRNA. The deduced amino acid sequences for small T antigen and the part of large T antigen markedly resembled those of polyoma virus BK and simian virus 40. The results strongly suggest that polyoma virus JC has the same organization of early genome as polyoma virus BK and simian virus 40 on the physical map, with the EcoRI site as a reference point.

Amino Acid Sequence↗

Progressive multifocal leukoencephalopathy. Diagnosis by in situ hybridization with a biotinylated JC virus DNA probe using an automated Histomatic Code-On slide stainer.

The accurate surgical pathological diagnosis of progressive multifocal leukoencephalopathy (PML) depends on the demonstration of pathognomonic histological features in cerebral biopsy tissue. The diagnosis may be difficult, however, if only small tissue fragments are submitted from the center of a demyelinating lesion. Previous studies by other authors have established that in situ hybridization with a biotinylated JC virus DNA probe can be a valuable diagnostic adjunct because it identifies the virally infected cells with great specificity and does not depend on the larger specimen, which may be necessary for a firm histological diagnosis. To confirm and extend these findings, we have used a commercially available biotinylated JC virus DNA probe to demonstrate the presence of viral DNA in formalin-fixed, paraffin-embedded tissues from four open biopsies, four needle biopsies, and two autopsies of patients with PML. With the goal of making this procedure applicable to the general surgical pathology laboratory, this method was adapted to the Histomatic Code-On slide stainer. The Histomatic is a programmable, robotic instrument with walk-away capability for hybridization histochemistry. Operation of this instrument requires the same expertise as execution of immunocytochemistry. With the advent of commercially available JC virus DNA probes and an automated system for hybridization histochemistry, this technology for diagnosis of PML may enter the routine diagnostic surgical pathology laboratory.

Acquired Immunodeficiency Syndrome↗