Expression of JC virus T-antigen in a patient with MS and glioblastoma multiforme

OBJECTIVE: To investigate the presence of human polyomavirus JC virus genome and the expression of the viral oncoprotein T-antigen in neoplastic cells of a patient with MS and a glioblastoma multiforme. BACKGROUND: The postmortem examination of an immunocompetent patient with a neurologic disorder revealed the concurrence of MS plaques in the white matter of the brain and a glioblastoma multiforme in the region of the thalamus. METHODS AND RESULTS: PCR analysis of DNA from demyelinated plaques and the tumor area using primers derived from specific regions of the JC virus genome revealed the presence of viral DNA corresponding to the viral early and late genes. Further examination of the samples for the JC virus regulatory region identified the presence of sequences identical to JC virus Mad-4 and JC virus W1 viral isolates in the tumor and the demyelinated regions. Results from immunohistochemistry showed the detection of the viral early protein, T-antigen, and the cellular tumor suppressor protein, p53, in the nuclei of neoplastic cells. Interestingly, expression of T-antigen, but not p53, was observed in neurofilament-positive cells with neuronal morphology and in glial fibrillary acidic protein-positive astrocytes in the cortex juxtaposed to the MS plaques. Examination of viral late gene expression by immunohistochemistry showed no evidence for viral capsid proteins, thus ruling out productive replication of JC virus in the tumor and MS demyelinated plaques. CONCLUSIONS: These observations provide molecular and clinical evidence of the association of JC virus in the brain of a patient with concurrent glioblastoma multiforme and MS.     

Role of an AP-2-like element in transcriptional regulation of mouse mu-opioid receptor gene

Previously, several important cis-elements and trans-factors have been shown to play a functional role in the proximal promoter of mouse mu-opioid receptor (MOR) gene. In this study, we defined another functional element located the in -450 to -400 bp (translational start site designated as +1) region of the proximal promoter, which is also essential for the full promoter activity. It is designated as the morAP-2-like element for its sequence homologous to the consensus AP-2 element. Surprisingly, electrophoretic mobility shift analysis (EMSA) revealed that Sp1 and Sp3, but not AP-2 proteins, were specifically bound to the morAP-2-like element. Mutation of the morAP-2-like element, resulting in a loss of Sp binding, led to an approximately 35% decrease in activity, further confirming the positive role of the morAP-2-like element in MOR gene expression. Dephosphorylation of Sp proteins with alkaline phosphatase also decreased Sp binding to the morAP-2-like element in EMSA, suggesting phosphorylation of Sp is essential for its binding to this element. However, direct or indirect activation of PKA, a classical G-protein coupled signaling pathway, resulted in no significant change of Sp binding to the morAP-2-like element, nor of the promoter activity the SH-SY5Y cells, MOR expressing cells, suggesting that phosphorylation of Sp does not involve PKA. These results suggest that the binding of different phosphorylated forms of Sp proteins to the morAP-2-like element may contribute to the fine tuning of MOR expression in different cells.     

Patient with progressive multifocal leukoencephalopathy by in situ hybridization: comparison of in situ hybridization using isotopic and biotinylated probes

Ward et al developed biotinylated probes to hasten virus nucleic acid detection. We used these probes to trace SV 40 and JC virus nucleic acids in PML brain. This procedure visualizes the hybridization of viral sequences by affinity cytochemistry with avidin-biotin peroxidase complexes and diaminobenzidine. In the PML frozen white matter numerous oligodendroglial nuclei hybridized with JC virus biotinylated and tritium labelled probes in areas adjacent to active demyelination. Although tritium labeled probes was most sensitive and gave lowest background this biotinylated method showed be useful as a rapid diagnostic test for the specific detection of viral nucleic acid sequences in brain tissues from patients with central nervous system (CNS) infectious diseases.