Characterization of the transmissible gastroenteritis virus (TGEV) transcription initiation sequence. Characterization of TGEV TIS.

The ability of the TGEV transcription initiation sequence (TIS) to produce subgenomic RNAs was investigated by placing a reporter gene, chloramphenicol acetyltransferase (CAT) under the control of either the mRNA 6 or the mRNA 7 TISs. Both constructs only produced CAT in TGEV infected cells and the amount of CAT produced from the mRNA 7 TIS was less than from the mRNA 6 TIS. Mutations were made within and around the TISs and the effect on CAT production assayed. THe results showed that the TGEV TIS acted as a initiator of transcription for CAT, though the degree of base pairing between the TIS and leader RNA was not the only factor implicated in the control transcription.