Biology subjects

Harper, K. L.

Publications and source records attributed to Harper, K. L..

3 recordsLinked to original sources

bioRxiv2024

Virus-induced paraspeckle-like condensates are essential hubs for gene expression and their formation drives genomic instability

The nucleus is a highly structured environment containing multiple membrane-less bodies formed through liquid-liquid phase separation. These provide spatial separation and concentration of specific biomolecules enabling efficient and discrete processes to occur which regulate gene expression. One such nuclear body, paraspeckles, are comprised of multiple paraspeckle proteins (PSPs) built around the architectural RNA, NEAT1_2. Paraspeckle function is yet to be fully elucidated but has been implicated in a variety of developmental and disease scenarios. We demonstrate that Kaposis sarcoma-associated herpesvirus (KSHV) drives formation of structurally distinct paraspeckles with a dramatically increased size and altered protein composition that are essential for productive lytic replication. We highlight these virus-induced paraspeckle-like structures form adjacent to virus replication centres, functioning as RNA processing hubs for both viral and cellular transcripts during infection. Notably, we reveal that PSP sequestration into virus-induced paraspeckle-like structures results in increased genome instability during both KSHV and Epstein Barr virus (EBV) infection, implicating their formation in virus-mediated tumorigenesis.

microbiology↗

bioRxiv2023

Pseudouridine prevalence in Kaposi's sarcoma associated herpesvirus transcriptome reveals an essential mechanism for viral replication

Pseudouridylation is a prevalent RNA modification shown to occur in tRNAs, rRNAs, snoRNAs and most recently mRNAs and lncRNAs. Emerging evidence suggests that this dynamic RNA modification is implicated in altering gene expression by regulating RNA stability, modulating translation elongation and modifying amino acid substitution rates. However, the role of pseudouridylation in infection is poorly understood. Here we demonstrate that Kaposis sarcoma-associated herpesvirus (KSHV) manipulates the pseudouridylation pathway to enhance replication. We show the pseudouridine synthases (PUS), PUS1 and PUS7 are essential for efficient KSHV lytic replication, supported by the redistribution of both PUS1 and PUS7 to viral replication and transcription complexes. We present a comprehensive analysis of KSHV RNA pseudouridylation, revealing hundreds of modified RNAs at single-nucleotide resolution. Notably, we further demonstrate that pseudouridylation of the KSHV-encoded polyadenylated nuclear RNA (PAN) plays a significant role in the stability of PAN RNA and in the association of the KSHV ORF57 protein. Our findings reveal a novel and essential role of pseudouridine modification in the KSHV replication cycle.

microbiology↗

bioRxiv2021

CircHIPK3 dysregulation of the miR-30c/DLL4 axis is essential for KSHV lytic replication

Non-coding RNA (ncRNA) regulatory networks are emerging as critical regulators of gene expression. These intricate networks of ncRNA:ncRNA interactions modulate multiple cellular pathways and impact the development and progression of multiple diseases. Herpesviruses, including Kaposis sarcoma-associated herpesvirus, are adept at utilising ncRNAs, encoding their own as well as dysregulating host ncRNAs to modulate virus gene expression and the host response to infection. Research has mainly focused on unidirectional ncRNA-mediated regulation of target protein-coding transcripts; however, we have identified a novel host ncRNA regulatory network essential for KSHV lytic replication in B cells. KSHV-mediated upregulation of the host cell circRNA, circHIPK3, is a key component of this network, functioning as a competing endogenous RNA of miR-30c, leading to increased levels of the miR-30c target, DLL4. Dysregulation of this network highlights a novel mechanism of cell cycle control during KSHV lytic replication in B cells. Importantly, disruption at any point within this novel ncRNA regulatory network has a detrimental effect on KSHV lytic replication, highlighting the essential nature of this network and potential for therapeutic intervention.

microbiology↗