Although phiKMV phage resembles the well-studied podovirus T7 in overall genome architecture, it was the first known T7-like phage which encoded a single-subunit RNA polymerase gene downstream its DNA metabolism genes instead of in the early genomic region.
A giant virion-encapsulated RNAP polymerase which is co-injected (early transcription), a heterodimeric phage RNA polymerase (middle region) and the host RNA polymerase (recognizes late promoters).