In-Depth Temporal Transcriptome Profiling of an Alphaherpesvirus Using Nanopore Sequencing

In this work, a long-read sequencing (LRS) technique based on the Oxford Nanopore Technology MinION platform was used for quantifying and kinetic characterization of the poly(A) fraction of bovine alphaherpesvirus type 1 (BoHV-1) lytic transcriptome across a 12-h infection period. Amplification-based LRS techniques frequently generate artefactual transcription reads and are biased towards the production of shorter amplicons. To avoid these undesired effects, we applied direct cDNA sequencing, an amplification-free technique. Here, we show that a single promoter can produce multiple transcription start sites whose distribution patterns differ among the viral genes but are similar in the same gene at different timepoints. Our investigations revealed that the circ gene is expressed with immediate-early (IE) kinetics by utilizing a special mechanism based on the use of the promoter of another IE gene (bicp4) for the transcriptional control. Furthermore, we detected an overlap between the initiation of DNA replication and the transcription from the bicp22 gene, which suggests an interaction between the two molecular machineries. This study developed a generally applicable LRS-based method for the time-course characterization of transcriptomes of any organism.

Automated summary

This study utilized a long-read sequencing technique based on the Oxford Nanopore Technology MinION platform to characterize the transcriptome of bovine alphaherpesvirus type 1 (BoHV-1) over a 12-hour infection period. The research revealed the presence of multiple transcription start sites from a single promoter, with different distribution patterns across viral genes but similar patterns within the same gene at different timepoints. It was also discovered that the circ gene expressed with immediate-early (IE) kinetics by utilizing the promoter of another IE gene (bicp4) for transcriptional control. Additionally, an overlap between DNA replication initiation and transcription from the bicp22 gene was detected, suggesting an interaction between the two molecular processes.