Tiled Microarray Identification of Novel Viral Transcript Structures and Distinct Transcriptional Profiles During Two Modes of Productive Murine Gammaherpesvirus 68 Infection.

We applied a custom tiled microarray to examine murine gammaherpesvirus 68 (MHV68) polyadenylated transcript expression in a timecourse of de novo infection of fibroblast cells and following phorbol ester-mediated reactivation from a latently-infected B cell line. During de novo infection, all ORFs were transcribed and clustered into four major temporal groups that were overlapping, yet distinct from clusters based on the phorbol ester-stimulated B cell reactivation timecourse. High-density transcript analysis at two-hour intervals during de novo infection mapped gene boundaries with a 20-nt resolution, including a previously undefined ORF73 transcript and the MHV68 ORF63 homolog of KSHV vNLRP1. ORF6 transcript initiation was mapped by tiled array and confirmed by 5' RACE. The ~1.3 kb region upstream of ORF6 was responsive to lytic infection and MHV68 RTA, identifying a novel RTA-responsive promoter. Transcription in intergenic regions consistent with the previously defined expressed genomic regions was detected during both types of productive infection. We conclude that the MHV68 transcriptome during de novo fibroblast infection and upon phorbol ester-stimulated B cell reactivation is dynamic and distinct, highlighting the need to evaluate further transcript structure and the context-dependent molecular events that govern viral gene expression during chronic infection. This SuperSeries is composed of the SubSeries listed below. Refer to individual Series