Quantitative expression of the HERV-W env gene in human tissues

Human endogenous retroviruses HERV-W families have been identified from monozygotic twin pairs with schizophrenia and patients with multiple sclerosis. Identification of retroviral RNA in the cerebrospinal fluids and brains of individuals with schizophrenia indicated that the transcriptional activation of the HERV-W elements within the central nervous system could be associated with the brain diseases. Here, we examined the expression of the HERV-W env gene in tumor/normal adjacent tissues and various areas of brain tissues. In silico expression data indicated that 14 complete HERV-W families from human chromosomes 1, 2, 4, 7, 8, 11, 13, 15, and Y are randomly expressed in various cancer tissues. HERV-W env transcripts did not show significant differences among the human tumor/normal adjacent tissues (colon, liver, uterus, breast, and stomach). Quantitative real-time RT-PCR analysis indicated that strong expression of the HERV-W env gene was detected in the cerebral cortex and pons of the human brain.