UBN-1 Background Information Epstein-Barr virus (EBV)-associated lymphoproliferative disorders frequently develop in patients with AIDS. The major target tissues for EBV infection are B lymphocytes and epithelial cells of the oropharyngeal zone (1,2). The protein product of the EBV BZLF1 early gene, EB1, interacts with viral and cellular promoters and transcription factors, thereby modulating the reactivation of EBV infection (1,3,4). The EB1 interacting protein, ubinuclein, is a product of the UBN1 gene and is expressed in the nucleus of human epidermis (1). The amino terminus of ubinuclein contains the nuclear localization signal whereas the central domain is responsible for the interaction of UBN-1 with the DNA-binding domain of EB1 (1,5).