Identification of a DNA-binding protein of human herpesvirus 6, a putative DNA polymerase stimulatory factor.

A 41K early nuclear antigen (p41), expressed in human herpesvirus type 6 (HHV-6)-infected T cells, was cloned by screening a cDNA expression library with the anti-p41 monoclonal antibody (MAb) C5. When expressed in mammalian cells, the cloned p41 protein comigrated with the authentic p41 protein from HHV-6-infected cells and localized to the nucleus. HHV-6 p41 shares 44% sequence identity with the human cytomegalovirus (HCMV) DNA-binding protein, ICP36 (UL44 gene product); p41 binds to ssDNA with the same apparent affinity as ICP36. Since ICP36 has recently been shown to be an HCMV DNA polymerase-associated stimulatory factor, a similar function is suggested for p41.