SRA

Abstract: The transcriptional program associated with herpesvirus latency and the viral genes regulating entry into and exit from latency are poorly understood and controversial. Here, we developed and validated a targeted enrichment platform and conducted large-scale transcriptome analyses of human cytomegalovirus (HCMV) infection. We used both an experimental hematopoietic cell model of latency, and cells from naturally infected, healthy human subjects (clinical) to define the breadth of viral genes expressed. The viral transcriptome derived from experimental infection was highly correlated with that from clinical infection, validating our experimental latency model. These transcriptomes revealed a broader profile of gene expression during infection in hematopoietic cells than previously appreciated. Further, using recombinant viruses that establish a non-reactivating, latent-like or replicative infection in CD34+ hematopoietic progenitors (HPCs), we defined classes of low to moderately expressed genes that are differentially regulated in latent vs. replicative states of infection. Most of these genes have yet to be studied in depth. By contrast, genes that were highly expressed, were expressed similarly in both latent and replicative infection.  From these findings, a model emerges whereby low or moderately expressed genes may have the greatest impact on regulating the switch between viral latency and replication. The core set of viral genes expressed in natural infection and differentially regulated depending on the pattern of infection provides novel insight into the HCMV transcriptome associated with latency in the host and a resource for investigating new virus-host interactions underlying persistence. Significance: Herpesviruses have an extraordinarily complex relationship with their host, persisting for the lifetime of the host by way of a latent infection. Reactivation of replication is associated with significant disease risk, particularly in immunocompromised individuals. We characterize in depth transcriptional profiles of HCMV latency. We show that a broad and concordant viral transcriptome is found in both an experimental model of latency and in asymptomatically infected individuals. We further define genes that are differentially regulated during latent and replicative states- candidates for key regulators controlling the switch between latency and reactivation. This work will help understand the persistence of complex DNA viruses and provides a path towards developing antiviral strategies to control herpesvirus entry into and exit from latency. Overall design: We sequenced a total of 49 samples. RNA-seq data sets refer to the following categories: (i) CD34+ HPC samples including mock, 2, 6 and 10dpi (n=30); (ii) Natural infection samples (pooled three samples due to low reads in individual samples). (iii) Fibroblast samples (n=16). We developed target probes (Agilent, SureSelect) to enrich low viral sequences. Our goal is to investigate HCMV transcriptomes in natural infection and experimental latency.