Sequence Analysis of the Left End of Fowl Adenovirus Genomes

Abstract

Nucleotide sequence analysis of the left end of the genome of fowl adenoviruses (FAdV) representing species group C (FAdV-4 and -10), D (FAdV-2) and E (FAdV-8) were carried out, and the sequence data was compared to those of FAdV-1 (FAdV-A) and FAdV-9 (FAdV-D). The viruses were propagated in chicken hepatoma cell line for viral DNA isolation. Restriction endonuclease analysis was performed followed by hybridization with two DNA probes representing the left end of FAdV-9. The identified fragments were sequenced, and the generated data were compared with the GenBank database. Nucleotide sequence homology and amino acid sequence identities were high between members of the same species group, FAdV-2 and -9, and FAdV-4 and -10, whereas different degrees of variations were observed among all FAdVs. Gene arrangement and position of ORFs at the left end of FAdV genomes were largely conserved suggesting similar gene functions. All previously characterized left end ORFs in CELO virus and FAdV-9 were found in all analyzed FAdVs. However, ORF 1C was absent in FAdV-4 and -10, but additional ORFs, most likely corresponding to duplicates of ORF 14, were observed in these viruses.

Whole-genome sequences of two turkey adenovirus types reveal the existence of two unknown lineages that merit the establishment of novel species within the genus Aviadenovirus

“…However, ORF14 and 14A are fused in TAdV-5 into the ORF14+14A. In the case of ORF1A, only the predicted second exon could be identified as in all earlier sequenced FAdV and TAdV genomes (except in FAdV-8, where it was described as a complete gene) (Corredor et al, 2006;Davison et al, 2003;Kaján et al, 2010;Marek et al, 2013).…”

Sequence comparison of the right end of fowl adenovirus genomes

“…So far, the complete nucleotide sequence has been determined only for FAdV-1 (CELO virus) and FAdV-9 strain A-2A (formerly named FAdV-8) [2,5]. Recently, nucleotide sequences of the left end of the FAdV genomes representing species groups C, D, and E have been determined, and those have shown some conservation in their open reading frames (ORFs) in terms of their relative positions, gene orientation, and amino acid sequence identities [6].…”

A region at the left end of the fowl adenovirus 9 genome that is non-essential in vitro has consequences in vivo

“…However, ORFs 1 and 1C have predictable functions. ORF1, present in all analysed FAdVs (Corredor et al, 2006), encodes the viral dUTPase that may be important for in vivo replication, as demonstrated in other viruses (Chen et al, 2002). ORF1C has 36.8 % amino acid identity to the E5 oncoprotein of bovine papillomavirus type 1 (Ojkic & Nagy, 2000) and appears to have similar functions in downregulating major histocompatibility complex class I molecules (Marchetti et al, 2002).…”

“…FAdV serotypes are grouped into five species (Fowl adenovirus A-E), all belonging to the genus Aviadenovirus, family Adenoviridae (Benkő et al, 2005). Complete nucleotide sequences are available for the genomes of FAdV-1 (CELO virus) and FAdV-9 (strain A-2A) (Chiocca et al, 1996;Ojkic & Nagy, 2000), and partial nucleotide sequences are also available for the left and right ends of the genomes of FAdV-2, -4, -8 and -10 (strain C-2B) (Corredor et al, 2006(Corredor et al, , 2008. None of the early genes at the left and right ends of the FAdV genomes are homologues of the E1, E3 and E4 genes of mastadenoviruses, which infect mammals Chiocca et al, 1996).…”

“…AC_000013 (Davison et al, 2003), the left ends of FAdV genomes show the following open reading frame (ORF) arrangement: ORFs 0, 1 (dUTPase), 1A, 1B, 1C (absent from FAdV-4 and -10), 2 (Rep protein), 24 (absent from FAdV-1), 14, 13 and 12 (Corredor et al, 2006). ORF15, an additional leftward-oriented ORF overlapping ORF14, is not annotated in GenBank accession no.…”