Identification and expression analysis of human endogenous retrovirus Y (HERV-Y) in various human tissues.

Human endogenous retroviruses (HERVs) account for approximately 8% of the human genome. To date, several HERV families have been identified in the human genome, with some being valid biomarkers for specific disease states. In this study, we have identified three HERV-Y elements in the human genome and characterized their structure and expression in various human tissues. New HERV-Y elements (HERV-Y101, HERV-Y102, and HERV-Y103) were detected on human chromosomes 8 and 13. In a pol-based phylogenetic tree, HERV-Y elements were closely grouped with HERV-I, -T, -E, and -R. The HERV-Y pol gene was expressed ubiquitously in all examined tissues, and it was dominantly expressed in the pons among the 12 different brain regions investigated. These results will allow future studies to elucidate the potential functional roles of HERVs in the brain and other tissues.