Biology subjects

Miranda, J. L.

Publications and source records attributed to Miranda, J. L..

3 recordsLinked to original sources

bioRxiv2025

Human Papillomavirus Genomes Associate with Active Host Chromatin during Persistent Viral Infection

Human papillomaviruses (HPVs) maintain their genomes as minichromosomes in the nuclei of infected keratinocytes. This study investigates the association of HPV31 genomes with host chromatin using both HiC and 4C-seq chromosome conformation capture techniques. We show that HPV31 genomes preferentially associate with transcriptionally active A compartments of host chromatin, regions of open chromatin defined by ATAC-seq, and super-enhancers defined by Brd4 and H3K27ac ChIP-seq. The viral genome association sites were also highly correlated with genomic loci previously identified as common HPV integration sites in cervical cancers. Recent studies have shown that transcriptionally active sites are prone to dsDNA breaks, and we find a strong correlation among dsBREAK datasets with transcriptionally active and open regions of host chromatin and the HPV31 genome association sites defined in our study. These findings suggest that HPV genomes associate with cellular transcriptional epicenters to maintain active viral gene expression during persistent infection, but also indicate that the susceptibility of these regions to dsDNA breaks could explain their propensity for viral DNA integration in HPV-associated cancers.

genomics↗

bioRxiv2017

The Epstein-Barr virus episome maneuvers between nuclear chromatin compartments during reactivation

The human genome is structurally organized in three-dimensional space to facilitate functional partitioning of transcription. We learned that the latent episome of the human Epstein-Barr virus (EBV) preferentially associates with gene-poor chromosomes and avoids gene-rich chromosomes. Kaposis sarcoma-associated herpesvirus behaves similarly, but human papillomavirus does not. Contacts localize on the EBV side to OriP, the latent origin of replication. This genetic element, and the EBNA1 protein that binds there, are sufficient to reconstitute chromosome association preferences of the entire episome. Contacts localize on the human side to gene-poor regions of chromatin distant from transcription start sites. Upon reactivation from latency, however, the episome moves away from repressive heterochromatin and toward active euchromatin. Our work adds three-dimensional relocalization to the molecular events that occur during reactivation. Involvement of a myriad of interchromosomal associations also suggests a role for this type of long - range association in gene regulation.\n\nIMPORTANCEThe human genome is structurally organized in three-dimensional space, and this structure functionally affects transcriptional activity. We set out to investigate whether a double stranded DNA virus, Epstein-Barr virus (EBV), uses similar mechanisms as the human genome to regulate transcription. We found that the EBV genome associates with repressive compartments of the nucleus during latency and active compartments during reactivation. This study is advances our knowledge of the EBV life cycle, adding three-dimensional re-localization as a novel component to the molecular events that occur during reactivation. Furthermore, the data adds to our understanding of nuclear compartments, showing that disperse interchromosomal interactions may be important for regulating transcription.

microbiology↗

bioRxiv2017

JQ1 reduces Epstein-Barr virus-associated lymphoproliferative disease in mice without sustained oncogene repression

Small molecule inhibitors of bromodomain and extra-terminal (BET) proteins are seeing increased investigation in clinical trials for treatment of hematological malignancies. These compounds also repress oncogene expression driven by the human Epstein-Barr virus (EBV) in cell culture. We therefore tested the efficacy of the prototypical BET inhibitor JQ1 against a mouse xenograft model of post-transplantation lymphoproliferative disorder. JQ1 potently inhibits growth of lymphoblastoid cell lines (LCLs) in culture at low nM concentrations. Growth of other cell lines with similar EBV type III latency transcription programs is comparably inhibited. JQ1 also slows tumor development of an LCL xenograft in immunocompromised mice, but oncogene repression is not observed in endpoint biopsies. We find reduction of EBV-associated lymphoproliferative disease in an animal model encouraging of further studies.

cancer biology↗