Transfer vectors and microorganisms containing human cytomegalovirus immediate-early promoter-regulatory DNA sequence

The cloning of a eucaryotic promoter-regulatory region that functions preferentially in human cells is disclosed. The invention is exemplified by the cloning of a section of the human cytomegalovirus genome comprising a DNA sequence with regulatory and promoter signals and an initiation site for RNA synthesis. The fragment, termed the human cytomegalovirus (HCMV) promoter-regulatory sequence, was obtained from purified HCMV DNA.