Human foamy virus Bel 1 transactivator/estrogen receptor fusion proteins allow inducible transactivation of both human foamy virus promoters

Lnc-RP5 Regulates the miR-129-5p/Notch1/PFV Internal Promoter Axis to Promote the Expression of the Prototype Foamy Virus Transactivator Tas

Prototype foamy virus (PFV) is a unique retrovirus that infects animals and humans and does not cause clinical symptoms. Long noncoding RNAs (lncRNAs) are believed to exert multiple regulatory functions during viral infections. Previously, we utilized RNA sequencing (RNA-seq) to characterize and identify the lncRNA lnc-RP5-1086D14.3.1-1:1 (lnc-RP5), which is markedly decreased in PFV-infected cells. However, little is known about the function of lnc-RP5 during PFV infection. In this study, we identified lnc-RP5 as a regulator of the PFV transcriptional transactivator (Tas). Lnc-RP5 enhanced the activity of the PFV internal promoter (IP). The expression of PFV Tas was found to be promoted by lnc-RP5. Moreover, miR-129-5p was found to be involved in the lnc-RP5-mediated promotion of PFV IP activity, while the Notch1 protein suppressed the activity of PFV IP and the expression of Tas. Our results demonstrate that lnc-RP5 promotes the expression of PFV Tas through the miR-129-5p/Notch1/PFV IP axis. This work provides evidence that host lncRNAs can manipulate PFV replication by employing miRNAs and proteins during an early viral infection.

The Novel Landscape of Long Non-Coding RNAs in Response to Human Foamy Virus Infection Characterized by RNA-Seq

Human foamy virus (HFV) is a complex and unique retrovirus with the longest genomes among retroviruses that are used as vectors for gene therapy. Long non-coding RNAs (lncRNAs) are regarded as key regulators that are involved in diverse biological processes during viral infection. However, the role of lncRNAs in HFV infection remains unknown. In this study, we utilized next-generation sequencing to first characterize lncRNAs in 293T cells after HFV infection, evaluating length distribution, exon number distribution, volcano picture, and lncRNA class distribution. We identified 11,336 lncRNAs (4,729 upregulated lncRNAs and 6,588 downregulated lncRNAs) and 61,367 mRNAs (30,133 upregulated mRNAs and 31,220 downregulated mRNAs), which were differentially expressed in the HFV-infected 293T cells. Subsequently, six differentially expressed lncRNAs characterized using RNA-seq were confirmed by quantitative real-time polymerase chain reaction assays. Interestingly, Gene Ontology (GO)/Gene Ontology Tree Machine (GOTM) and Kyoto Encyclopedia of Gene and Genomes (KEGG) pathway analyses indicated that positive regulation of interleukin 8 (IL8) production and cytokine-cytokine receptor interaction might be involved in the functional enrichment of lncRNAs. Moreover, cis-acting and trans-acting regulatory networks show that NR_028036 may target the fas gene in a cis-acting manner and that ENST00000354838 may target the IL18 gene in a trans-acting manner. Overall, these results not only provide novel insights into the relationship between HFV and lncRNAs in the host response to infection but also have implications for the future wider application of HFV as a vector.