T7 DNA-dependent RNA polymerase can transcribe RNA from tick-borne encephalitis virus (TBEV) cDNA with SP6 promoter.

T7 RNA polymerase is shown to recognize the SP6 promoter including 17 base pairs before the transcription start site and produce the 5'-end TBEV RNA. The yield of TBEV RNA synthesized by heterologous T7 RNA polymerase from cDNA construction with SP6 promoter is higher than the RNA production by homologous SP6 RNA polymerase. The addition of 1 pmol template DNA with SP6 17 bp promoter in transcription mixture for SP6 or T7 RNA polymerases resulted in a 1-5 X 10(-2) pmol RNA production.