Transcription of HE-EGFP vRNA from rISAV. RT-PCR of RNA from supernatant of cells cotransfected with 12 plasmids, including the pSS-URG/S6-EGFP-HPR plasmid, used to generate rISAVS6/EGFP-HPR. vRNA was amplified utilizing specific primers (Table 2) directed to the EGFP gene only (left), segment 6 only (middle), and the chimeric region containing part of both segment 6 and EGFP (right). Mock corresponds to supernatants from untransfected ASK cells, ISAV_901_09 corresponds to supernatant obtained from ASK cells infected with the WT ISAV 901 strain, and rISAVS6/EGFP-HPR corresponds to supernatants obtained from ASK cells infected with rISAVS6/EGFP-HPR. Experiments were performed two times with similar results.