Genome organization and transcription strategy of the NS segment. Open reading frames (ORFs) are marked by the colored arrows and boxes, mRNA is stylized by the black lines. Small open reading frames, which function as exons, but lack a canonical ATG start codon, are marked by an asterisk (*). The wavy lines mark polyadenylation signals. Promoters are labeled as P, donor- and acceptor sites as D and A respectively. Below the promoters the sequence of the transcription start site is shown, with the actual mRNA 5' end presented in bold behind the vertical line. The estimated molecular weights of the protein products to be expressed by each transcript are shown to the right.
