Ishaq M, Stoner G L
Laboratory of Experimental Neuropathology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.
Proc Natl Acad Sci U S A. 1994 Aug 16;91(17):8283-7. doi: 10.1073/pnas.91.17.8283.
JC virus (JCV) causes progressive multifocal leukoencephalopathy (PML), the fatal demyelinating infection of oligodendrocytes, in up to 5% of AIDS patients. An intron-differential RNA PCR was developed to study the expression of alternately spliced JCV early mRNAs in brain tissues from PML patients with and without AIDS and in JCV-induced hamster brain tumors. The method utilizes primers that span the large tumor (T) and small tumor (t) antigen introns allowing amplification of specific cDNAs in the presence of contaminating viral genomic DNA. Hybridization with specific junctional probes and DNA sequence analysis confirmed the identity of the PCR products. Sequencing showed that JCV early mRNA is alternatively spliced as previously predicted by analogy to simian virus 40. Large T antigen mRNA was detected in all the brain tissues from PML patients with and without AIDS. The expression of small t antigen mRNA varied depending upon the association of PML with AIDS and upon other unknown factors. Of the 12 PML/AIDS brain tissue samples, 11 (92%) expressed small t antigen mRNA, whereas only 8 of 13 (62%) brain samples from patients with PML alone showed detectable levels of small t antigen mRNA. Human immunodeficiency virus 1 proviral DNA was detected in 10 of 12 PML/AIDS brain samples. The results indicate that alternative splicing of JCV early mRNA is regulated in the human brain and that the production of small t antigen may not be essential for the pathogenesis of PML.
JC病毒（JCV）可导致进行性多灶性白质脑病（PML），这是一种少突胶质细胞的致命性脱髓鞘感染，在高达5%的艾滋病患者中出现。开发了一种内含子差异RNA聚合酶链反应（PCR）来研究PML患者（有或无艾滋病）脑组织以及JCV诱导的仓鼠脑肿瘤中交替剪接的JCV早期mRNA的表达。该方法利用跨越大小肿瘤（T）抗原和小肿瘤（t）抗原内含子的引物，在存在污染性病毒基因组DNA的情况下扩增特定的cDNA。与特异性连接探针杂交和DNA序列分析证实了PCR产物的身份。测序表明，JCV早期mRNA如先前通过与猴病毒40类比所预测的那样进行交替剪接。在有或无艾滋病的PML患者的所有脑组织中均检测到了大T抗原mRNA。小t抗原mRNA的表达因PML与艾滋病的关联以及其他未知因素而异。在12个PML/艾滋病脑组织样本中，11个（92%）表达小t抗原mRNA，而仅患PML患者的13个脑样本中有8个（62%）显示出可检测水平的小t抗原mRNA。在12个PML/艾滋病脑样本中的10个中检测到了人类免疫缺陷病毒I型前病毒DNA。结果表明，JCV早期mRNA的交替剪接在人脑中受到调控，并且小t抗原的产生对于PML的发病机制可能并非必不可少。
