KSHV LANA1 binds DNA as an oligomer and residues N-terminal to the oligomerization domain are essential for DNA binding, replication, and episome persistence

Abstract

Latency-associated nuclear antigen 1 (LANA1) binds to Kaposi's sarcoma-associated herpesvirus (KSHV) terminal repeat (TR) DNA to mediate episome replication and persistence. LANA1 concentrates at sites of TR DNA along mitotic chromosomes, consistent with tethering KSHV DNA to chromosomes for efficient segregation of episomes to progeny nuclei. We now investigate LANA1 C-terminus self-association and DNA binding. The TR DNA binding domain was localized to LANA1 residues 996–1139. Scanning deletions within this region ablated both LANA1 oligomerization and DNA binding, consistent with a requirement for oligomerization to bind DNA. Furthermore, LANA1 bound TR DNA as an oligomer. Deletion of amino acids 1007–1021, N-terminal to the LANA1 oligomerization domain, ablated DNA binding, DNA replication, and episome persistence, implicating these residues in contacting DNA. Indeed, LANA1 residues 1007–1021 correspond to EBNA1 residues that contact the cognate sequence. Like EBNA1, the LANA1 DNA-binding domain has oligomerization activity and critical residues essential for recognizing DNA.