Associates with RNA polymerase to initiate transcription from late gene promoters. Interacts with the late transcription factors VLTF-2 and VLTF-3. Interacts with the late transcription elongation factor H5/VLTF-4. Interacts with itself (By similarity). Expressed in the intermediate phase of the viral replicative cycle. Belongs to the chordopoxvirinae VLTF-1 family.