Figure 1.

Generation of rTGEV-SPEDV viruses. (A) Diagram of the chimeric spike (S) protein expressed by the virus. A representation of spike peplomer is indicated in the left. The scheme on the right indicates the S protein sequence from porcine epidemic diarrhea virus (PEDV) and from TGEV. Relevant S protein domains are indicated: NE, domains recognized by neutralizing antibodies; HR, heptad repeat domain; TM, transmembrane domain. (B) Scheme of the recombinant TGEV virus genome encoding a chimeric S protein (SPEDV-TGEV). Labels above the boxes indicate viral genes. L, leader sequence; An, poly A tail. (C) Scheme of the rTGEV virus expressing the chimeric S protein from an attenuated background containing transcription regulating sequences (TRSs) duplication and the introduction of restriction sites, as described in [46]. Engineered restriction sites are in italics, duplicated sequences (Dup. Seq.) into grey boxes. Each gene is in a color box as in the upper virus genome scheme, with stop and ATG codons indicated.