Patent ID: 8685645

Claim:
A method of screening for an enhancer and/or a promoter, the method comprising: (A) culturing a host cell into which an amplifiable plasmid vector is introduced, wherein the host cell does not comprise a T antigen gene of simian virus 40 in its genome, the amplifiable plasmid vector comprising; (a) a DNA fragment to be determined, and a first transcription termination sequence that is functionally linked upstream of the DNA fragment, (b) a minimal CMV promoter that is functionally linked downstream of the DNA fragment, (c) a large T antigen gene of simian virus 40 that is functionally linked downstream of the minimal CMV promoter, and (d) a second transcription termination sequence functionally linked downstream to the large T antigen gene and a sequence that encodes a replication origin sequence of simian virus 40 that is functionally linked downstream to the second transcription termination sequence, (B) extracting the vector from the host cell; and (C) obtaining the DNA fragment from the extracted vector.