The Kaposi's sarcoma-associated herpesvirus latency-associated nuclear antigen binds to specific sequences at the left end of the viral genome through its carboxy-terminus

Latent infection by members of the gammaherpesvirus family is typically characterized by stable episomal maintenance of genomic viral DNA. In the case of Epstein-Barr virus (EBV), this is dependent upon binding of the Epstein-Barr nuclear antigen 1 (EBNA1) to sites which lie within the origin of plasmid replication (OriP). The recently discovered Kaposi's sarcoma-associated herpesvirus (KSHV) encodes the latency-associated nuclear antigen (LANA), which appears to be important for supporting the latent infection of human cells by KSHV. The present work describes site-specific binding of the LANA protein to multiple different elements at the left end of the genome, a region which appears to be critical for maintenance of KSHV episomes. Of the three sites, terminal LANA-binding region 4 (TLBR4) binds LANA with the highest affinity when compared to the other sites. Further characterization of this cis-acting element by mutagenesis studies indicates that the minimal TLBR4-binding sequence is represented by a 13-bp sequence 5' CGCCCGGGCATGG 3'. Furthermore, this specific binding to TLBR4 was mediated by the distal 200 amino acid C-terminus of the LANA protein. (C) 2001 Elsevier Science.