Biology subjects

Zarrella, K.

Publications and source records attributed to Zarrella, K..

3 recordsLinked to original sources

bioRxiv2025

Human cytomegalovirus regulates host DNA repair machinery for viral genome integrity

The DNA damage response (DDR) encompasses a multitude of interconnected pathways that serve as a cellular defense to protect genome integrity. Dysregulation or failure of these pathways results in cancers and genetic disease. DNA viruses, including the herpesvirus cytomegalovirus (CMV), activate DDR signaling during their replicative program. The mechanisms by which they commandeer these responses for replication of their genome is less well understood. Here, we define a viral protein, UL138, that modulates the activity of host DDR pathways. The loss of UL138 results in structural variants, including inversion, deletions, duplication, with signature of homology-directed repair and other DDR pathways. The actions of UL138 are due, in part, to its modulation of pathways regulated by the cellular deubiquitinating complex that targets proliferating cell nuclear antigen (PCNA) and Fanconi Anemia effectors, FANCD2 and FANCI. However, we also show that UL138 accesses pathways independent of USP1-PCNA/FANCD2/FANCI. Disruption of UL138 or these pathways impacts viral genome replication and had consequences for viral genome integrity. This work provides mechanistic insight into the long-standing questions of how DNA viruses recruit, modulate and use cellular DDR pathways. It also puts forth CMV as a model system for further defining these pathways in human cells. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/683233v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@121e55borg.highwire.dtl.DTLVardef@58d8b7org.highwire.dtl.DTLVardef@fc1628org.highwire.dtl.DTLVardef@12b32a_HPS_FORMAT_FIGEXP M_FIG C_FIG Major findingsO_LIUL138 protects HCMV genome integrity through its interaction with USP1-PCNA/FANCD2/FANCI and repeat sequence-mediated pathways C_LIO_LIUL138 protects HCMV genome integrity in the UL region by mechanisms independent of repeat sequences and USP1-PCNA/FANCD2/FANCI C_LIO_LICollectively, US and UL regions of the HCMV genome have fundamentally different pathways acting on them and UL138 modulates DNA damage and repair pathway choice. C_LI

microbiology↗

bioRxiv2024

Viral and host network analysis of the human cytomegalovirus transcriptome in latency.

HCMV genes UL135 and UL138 play opposing roles regulating latency and reactivation in CD34+ human progenitor cells (HPCs). Using the THP-1 cell line model for latency and reactivation, we designed an RNA sequencing study to compare the transcriptional profile of HCMV infection in the presence and absence of these genes. The loss of UL138 results in elevated levels of viral gene expression and increased differentiation of cell populations that support HCMV gene expression and genome synthesis. The loss of UL135 results in diminished viral gene expression during an initial burst that occurs as latency is established and no expression of eleven viral genes from the ULb region even following stimulation for differentiation and reactivation. Transcriptional network analysis revealed host transcription factors with potential to regulate the ULb genes in coordination with pUL135. These results reveal roles for UL135 and UL138 in regulation of viral gene expression and potentially hematopoietic differentiation.

microbiology↗

bioRxiv2023

Human Cytomegalovirus UL138 Interaction with USP1 Activates STAT1 in infection

Innate immune responses are crucial for limiting virus infection. However, viruses often hijack our best defenses for viral objectives. Human Cytomegalovirus (HCMV) is a beta herpesvirus which establishes a life-long latent infection. Defining the virus-host interactions controlling latency and reactivation is vital to the control of viral disease risk posed by virus reactivation. We defined an interaction between UL138, a pro-latency HCMV gene, and the host deubiquintase complex, UAF1-USP1. UAF1 is a scaffold protein pivotal for the activity of ubiquitin specific peptidases (USP), including USP1. UAF1-USP1 sustains an innate immune response through the phosphorylation and activation of signal transducer and activator of transcription-1 (pSTAT1), as well as regulates the DNA damage response. After the onset of viral DNA synthesis, pSTAT1 levels are elevated and this depends upon UL138 and USP1. pSTAT1 localizes to viral centers of replication, binds to the viral genome, and influences UL138 expression. Inhibition of USP1 results in a failure to establish latency, marked by increased viral genome replication and production of viral progeny. Inhibition of Jak-STAT signaling also results in increased viral genome synthesis in hematopoietic cells, consistent with a role for USP1-mediated regulation of STAT1 signaling in the establishment of latency. These findings demonstrate the importance of the UL138-UAF1-USP1 virus-host interaction in regulating HCMV latency establishment through the control of innate immune signaling. It will be important going forward to distinguish roles of UAF1-USP1 in regulating pSTAT1 relative to its role in the DNA damage response in HCMV infection. ImportanceHuman cytomegalovirus (HCMV) is one of nine herpesviruses that infect humans. Following a primary infection, HCMV establishes a life-long latent infection that is marked by sporadic, and likely frequent reactivation events. While these reactivation events are asymptomatic in the immune competent host, they pose important disease risks for the immune compromised, including solid organ or stem cell transplant recipients. Its complex interactions with host biology and deep coding capacity make it an excellent model for defining mechanisms important for viral latency and reactivation. Here we define an interaction with host proteins that commandeer typically antiviral innate immune signaling for the establishment of latency.

microbiology↗