Genomes shown include Sendai virus (SeV, blue), respiratory syncytial virus (RSV, green), and a SeV-vectored vaccine that has the RSV F protein inserted between SeV F and HN genes (SeV-RSV). In each genome the 3’ leader is positioned on the left terminus and the 5’ trailer is on the right. Intergenic junctions between genes (not shown) contain transcription stop, intergenic, and transcription start sequences. In the SeV P gene, leaky scanning products include the C’, C, Y1, and Y2 proteins (brown). Also in the SeV P gene, mRNA editing produces V and W proteins that share their N-terminal portion with V (blue) and have an alternate reading frame in their C-terminal portion (orange). For simplicity, the alternate products from the P gene are omitted from the SeV-RSV schematic. In the RSV genome, the M2 gene contains two overlapping products, M2-1 and M2-2. The RSV M2 and L genes also overlap. Genomes are drawn to scale (bottom).