Tegument protein that plays a role in the inhibition of host intrinsic defenses to promote viral early gene activation. Interacts with host DAXX and thereby disrupts the complex between DAXX and ATRX. Suppresses the DAXX-ATRX dependent deposition of histone H3.3 on viral chromatin allowing viral transcription. May also play a role in virus entry at attachment or membrane fusion steps. Interacts with host DAXX; this interaction disrupts the chromatin remodeling complex ATRX:DAXX and thus allows viral transcription. Colocalizes with host DAXX at PML nuclear bodies. Belongs to the herpesviridae MTP family. Controvertial experiments have localized MTP at the virion surface.