Ball Python Nidovirus: a Candidate Etiologic Agent for Severe Respiratory Disease in Python regius

Stenglein, Mark D.; Jacobson, Elliott R.; Wozniak, Edward J.; Wellehan, James F. X.; Kincaid, Anne; Gordon, Marcus; Porter, Brian F.; Baumgartner, Wes; Stahl, Scott; Kelley, Karen; Towner, Jonathan S.; DeRisi, Joseph L.

In order to characterize these RNAs, we performed PCR using primer pairs separated by more than 23 kb of genomic sequence but that would amplify putative sgRNAs (Fig. 5A) (55) . PCR and sequencing of amplicons revealed sgRNA species for each of the predicted 3= ORFs, except for ORF5a and -5b, which appear to share a single mRNA. ORF5a and -5b overlap by 251 nt, and their start codons are separated by 208 nt (Fig. 5B and C) . The sgRNAs share a 5=-terminal "leader" sequence (approximately nt 1 to 170 of genome) (Fig. 5C ). Short regions of homology are evident at the junction points of the sgRNAs (Fig. 5C ). These data are consistent with this virus using a strategy of discontinuous RNA synthesis and translation similar to that employed by other nidoviruses (54) .