Genome sequence analysis
As revealed from the sequencing results, the complete genome of
DAstV-SDZZ comprised 7,757 nucleotides (nt) with a 34-nt poly(A) tail,
and was submitted to the GenBank (accession number MN809622), making it
the largest among astroviruses so far sequenced. The coding region of
DAstV-SDZZ strain consisting of three overlapping ORFs of 3,723 nt
(ORF1a), 1,551 nt (ORF1b) and 2,196 nt (ORF2), as well as a short 5’ UTR
of 22 nt and a 3’ UTR of 252 nt. The three sequential ORFs encoded
polypeptides of 1,240 (positions 23 to 3745), 516 (positions 3736 to
5286), and 731 (positions 5310 to 7505) amino acids, respectively.
Furthermore, a ribosomal frameshift signal was observed in the overlap
region between ORF1a and ORF1b of DAstV-SDZZ, consisting of the
heptameric sequence AAAAAAC from nt 3736 to 3742.