Toward a Transcriptional Map of the Turkey Turkey adenovirus 3 Genome

Abstract

, historically referred to as turkey hemorrhagic enteritis virus (THEV), causes immunosuppression and hemorrhagic enteritis in turkey poults. Although an avirulent TAdV-3 strain is used as a live vaccine, its immunosuppressive properties remain poorly understood at the molecular level. Here, we employed Rapid Amplification of cDNA Ends (RACE) and Sanger sequencing to generate a transcriptomic map of TAdV-3 infected MDCTRP-19 cells at 24 hours post infection.Using RACE and virus-specific primers, we obtained full-length annotation of 14 out of 23 predicted viral transcripts. Analysis of late structural genes revealed a conserved tripartite leader (TPL) sequence shared across all late transcripts, providing new insights into their transcription start sites, splicing events, and promoter architecture.Additionally, we identified alternative leader exons-for instance, DBP mRNA contains a bipartite leader, whereas Hyd mRNA utilizes the TPL-and observed coordinated 3' end processing via shared polyadenylation signals between certain transcripts (e.g., ORF1 and Hyd). This precise annotation of TAdV-3 mRNAs lays the groundwork for linking transcript structure to protein function, enhancing our understanding of TAdV-3's immunosuppressive strategies and informing future development of TAdV-3 based gene delivery platforms.