Immunohistochemical detection of JC virus in nontumorous renal tissue of a patient with renal cancer but without progressive multifocal leukoencephalopathy.
We performed immunohistochemical staining on the nontumorous renal tissue of 45 patients with renal cancer but without progressive multifocal encephalopathy using JCV-specific antibody. For one patient we found positive staining of the nuclei of the renal collecting ducts. Immunoelectron microscopic examination of the positive cell nuclei revealed electron-dense polyomavirus-like particles. (+info)
The J domain of papovaviral large tumor antigen is required for synergistic interaction with the POU-domain protein Tst-1/Oct6/SCIP.
Large T antigens from polyomaviruses are multifunctional proteins with roles in transcriptional regulation, viral DNA replication, and cellular transformation. They have been shown to enhance the activity of various cellular transcription factors. In the case of the POU protein Tst-1/Oct6/SCIP, this enhancement involves a direct physical interaction between the POU domain of the transcription factor and the amino-terminal region of large T antigen. Here we have analyzed the structural requirements for synergistic interaction between the two proteins in greater detail. Tst-1/Oct6/SCIP and the related POU protein Brn-1 were both capable of direct physical interaction with large T antigen. Nevertheless, only Tst-1/Oct6/SCIP functioned synergistically with large T antigen. This differential behavior was due to differences in the amino-terminal regions of the proteins, as evident from chimeras between Tst-1/Oct6/SCIP and Brn-1. Synergy was specifically observed for constructs containing the amino-terminal region of Tst-1/Oct6/SCIP. Large T antigen, on the other hand, functioned synergistically with Tst-1/Oct6/SCIP only when the integrity of its J-domain-containing amino terminus was maintained. Mutations that disrupted the J domain concomitantly abolished the ability to enhance the function of Tst-1/Oct6/SCIP. The J domain of T antigen was also responsible for the physical interaction with Tst-1/Oct6/SCIP and could be replaced in this property by other J domains. Intriguingly, a heterologous J domain from a human DnaJ protein partially substituted for the amino terminus of T antigen even with regard to the synergistic enhancement of Tst-1/Oct6/SCIP function. Given the general role of J domains, we propose chaperone activity as the underlying mechanism for synergy between Tst-1/Oct6/SCIP and large T antigens. (+info)
Reciprocal interaction between two cellular proteins, Puralpha and YB-1, modulates transcriptional activity of JCVCY in glial cells.
Cross communication between regulatory proteins is an important event in the control of eukaryotic gene transcription. Here we have examined the structural and functional interaction between two cellular regulatory proteins, YB-1 and Puralpha, on the 23-bp sequence element derived from the enhancer-promoter of the human polyomavirus JCV. YB-1 and Puralpha are single-stranded DNA binding proteins which recognize C/T- and GC/GA-rich sequences, respectively. Results from band shift studies demonstrated that while both proteins interact directly with their DNA target sequences within the 23-bp motif, each protein can regulate the association of the other one with the DNA. Affinity chromatography and coimmunoprecipitation provide evidence for a direct interaction between Puralpha and YB-1 in the absence of the DNA sequence. Ectopic expression of YB-1 and Puralpha in glial cells synergistically stimulated viral promoter activity via the 23-bp sequence element. Results from mutational studies revealed that residues between amino acids 75 and 203 of YB-1 and between amino acids 85 and 215 of Puralpha are important for the interaction between these two proteins. Functional studies with glial cells indicated that the region within Puralpha which mediates its association with YB-1 and binding to the 23-bp sequence is important for the observed activation of the JCV promoter by the Puralpha and YB-1 proteins. The results of this study suggest that the cooperative interaction between YB-1 and Puralpha mediates the synergistic activation of the human polyomavirus JCV genome by these cellular proteins. The importance of these findings for cellular and viral genes which are regulated by Puralpha and YB-1 is discussed. (+info)
Clinical and virological monitoring during treatment with intrathecal cytarabine in patients with AIDS-associated progressive multifocal leukoencephalopathy.
We describe the clinical and virological outcome of human immunodeficiency virus-infected patients with progressive multifocal leukoencephalopathy (PML) treated with cytarabine. Twenty-seven patients received intrathecal cytarabine, 5 received concomitant intravenous cytarabine, and 20 received concomitant antiretroviral therapy. The median baseline CD4+ cell count was 28/mm3. After 4 weeks, 4 (19%) of 21 evaluable patients had stable disease, whereas the others progressed. The median survival from diagnosis and from onset was 66 and 128 days, respectively. Patients with Karnofsky scores of >50 and those previously taking antiretroviral medications had a higher probability of survival 3 months after diagnosis (P = .003 and P = .05, respectively). Overall, after 4 weeks, median JC virus load in CSF increased by 0.7 log10 copies/mL from baseline (P = NS). The mean JC virus load at 4 weeks was lower in patients with stable disease than in progressors (3.47 vs. 4.47 log10 copies/mL; P = .027). JC virus became undetectable in the only patient who had a long-term stable condition. The concentration of JC virus in CSF showed a correlation with clinical outcome. (+info)
Molecular cloning and expression of major structural protein VP1 of the human polyomavirus JC virus: formation of virus-like particles useful for immunological and therapeutic studies.
The major structural viral protein, VP1, of the human polyomavirus JC virus (JCV), the causative agent of progressive multifocal leukoencephalopathy (PML), was expressed by using recombinant baculoviruses. Recombinant VP1 formed virus-like particles (VLP) with the typical morphology of empty JCV capsids. Purified VP1 VLP bind to SVG, B, and T cells, as well as to monkey kidney cells. After binding, VP1 VLP were also internalized with high efficiency and transported to the nucleus. Immunization studies revealed these particles as highly immunogenic when administered with adjuvant, while immunization without adjuvant induced no immune response. VP1 VLP hyperimmune serum inhibits binding to SVG cells and neutralizes natural JCV. Furthermore, the potential of VP1 VLP as an efficient transporter system for gene therapy was demonstrated. Exogenous DNA could be efficiently packaged into VP1 VLP, and the packaged DNA was transferred into COS-7 cells as shown by the expression of a marker gene. Thus, VP1 VLP are useful for PML vaccine development and represent a potential new transporter system for human gene therapy. (+info)
Viral variant nucleotide sequences help expose leukocytic positioning in the JC virus pathway to the CNS.
The human polyomavirus JCV lytically infects oligodendrocytes of immunosuppressed individuals leading to the fatal demyelinating disease termed progressive multifocal leukoencephalopathy (PML). Dementia, hemiparesis, and hemianopsia are the predominant presenting signs of PML. Asymptomatic JCV infection is common worldwide with approximately 80% of adults testing positive for JCV antibodies. In addition to the brain, JCV has been shown to infect tonsil, lymphoid, bone marrow, and kidney tissues. Viral variants, classified according to the nucleotide sequences of their regulatory regions, are being mapped in human tissues and cell types to help trace the pathway of JCV from a site of initial infection to target oligodendrocytes. In most literature, a dichotomy of the JCV regulatory region structure exists by tissue. B lymphocytes, however, have demonstrated the capacity to harbor JCV of diverse regulatory regions, which helps position their interaction with virus amid every stage of infection and implicates a lymphocytic role in latency. (+info)
Archetypal and rearranged sequences of human polyomavirus JC transcription control region in peripheral blood leukocytes and in cerebrospinal fluid.
Two forms of human polyomavirus JC (JCV) genome are known based upon the structure of the transcriptional control region (TCR) of the virus: the archetypal form, which is commonly detected in urine, and the rearranged form, which was first detected in brain tissue from progressive multifocal leukoencephalopathy (PML) patients. The latter actually includes a group of TCR variants that, relative to the former, are characterized by various deletions and/or duplications. The aim of this study was to establish whether or not a correlation exists among the TCR type, the spreading of the virus within the host and its ability to cause PML. JCV TCR sequences from peripheral blood leukocytes (PBL) and cerebrospinal fluid (CSF) obtained from various groups of patients were compared. JCV with archetypal TCR was detected in CSF and PBL specimens from patients without neurological disorders or who eventually received a diagnosis of a non-PML neurological disorder. Rearranged TCR sequences were detected in all the CSF and PBL specimens from PML patients. The high similarity observed between the TCR structure detected in PBL and CSF specimens from individual patients could strengthen the hypothesis that PBL has a role in spreading JCV to the brain. Moreover, heterogeneous TCR patterns have been shown in individual PBL specimens from PML patients. This supports the hypothesis that, in PBL, JCV may replicate and undergo rearrangements of the TCR. The detection of JCV DNA by PCR in CSF independently from PML, although rare, could suggest that this assay is not sufficient for a virological diagnosis of PML. Further studies are required to assess the usefulness of quantitative assays or TCR typing in combination with PCR for diagnostic purposes. (+info)
Progressive multifocal leukoencephalopathy in a patient with acquired immunodeficiency syndrome (AIDS) manifesting Gerstmann's syndrome.
We reported a case of acquired immunodeficiency syndrome (AIDS) via multiple blood transfusions, who manifested progressive multifocal leukoencephalopathy (PML) about 18 months after the development of AIDS. PML initiated with right hemiparesis, dysphasia, and Gerstmann's syndrome and resulted in death within 2 months after the onset. Neuroimaging examinations revealed white matter lesions mainly in the left posterior parietal lobe. The cortical gray matter also showed abnormal signal intensity. Peripheral CD4+ lymphocyte count was 81/microl. Routine cerebrospinal fluid (CSF) examinations were negative. CSF antibodies against herpes simplex virus, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus as well as serum antibody against toxoplasma gondii were negative. Though autopsy or biopsy of the brain was not performed, JC virus genomes were detected in the CSF sample by a polymerase chain reaction, and their sequencing showed unique alterations of the regulatory regions, characteristic to PML-type JC virus. (+info)