The period from 1970 to 1981 established the core paradigm of studying viral polymerase mechanisms through cell-free, promoter-dependent transcription systems. Researchers integrated viral templates to reveal promoter DNA requirements and to dissect transcription mechanics with high experimental control, thereby uniting virology with general transcription concepts. Parallel work mapped viral transcription units and linked initiation with RNA processing events such as capping, underscoring the coupling of transcription and RNA maturation. The results highlighted promoter-like DNA motifs and RNA polymerase–DNA recognition patterns that guided subsequent research into viral and cellular transcription logic.