Biology subjects

Weller, S. K.

Publications and source records attributed to Weller, S. K..

4 recordsLinked to original sources

bioRxiv2026

PXL: a Nucleic Acid-Binding Module of Promyelocytic Leukemia Protein

The promyelocytic leukemia protein (PML) is a stress-response factor that assembles into PML nuclear bodies, dynamic subnuclear compartments involved in tumor suppression and antiviral defense. The most abundant isoform, PML-1, has been linked to transcriptional regulation, genome stability, and antiviral responses, yet the molecular basis of these functions remains unclear. Here, we report that PML-1 contains a unique nucleic acid- binding module, PXL, and determine its three-dimensional structure by X-ray crystallography. Further biochemical, mutational, and cellular analyses, including RNA-seq, demonstrate that this module selectively binds single-stranded G-rich RNA and DNA motifs and modulates the transcriptome. These findings reveal an unexpected molecular function of PML and provide a framework for understanding its roles in nuclear organization and gene regulation.

biochemistry↗

bioRxiv2026

Conserved assembly architecture of the essential herpesvirus packaging accessory factor

To create a new wave of infectious virions, all herpesviruses require an accessory factor of unknown function to package their viral genomes into nascent capsids. Here, we present cryo-EM structures of the packaging accessory factor from the -herpesvirus herpes simplex virus type 1 (HSV-1, UL32) and the {beta}-herpesvirus human cytomegalovirus (HCMV, UL52). Unlike homologs from the {gamma}-herpesviruses, neither UL32 nor UL52 form stable homopentameric rings. UL52 forms incomplete pentameric rings lacking one or two protomers. UL32 does not form stable higher-order species, but stabilization through chemical crosslinking revealed a novel quaternary structure where three pentameric rings assemble into a "tripentamer." Our results reveal that herpesvirus packaging accessory factors adopt distinct oligomeric states but are constrained to pentameric symmetry. Assembly of protomers into a ring creates a positively charged central channel that we show is critical for infectious virus production in HSV-1. Taken together, our study points to a structurally conserved, essential function of packaging accessory factors across the Herpesviridae. AUTHOR SUMMARYHerpesviruses are a diverse family of pathogens that drive human disease. At the end of their life cycle, all herpesviruses must actively package their genomes into newly formed capsids. Although some aspects of packaging are conserved with tailed bacteriophages, herpesviruses require an additional packaging accessory factor of unknown function. Here, we present two high-resolution structures of the packaging accessory factor from herpes simplex virus and human cytomegalovirus and identify pentameric symmetry as a unifying structural feature. We propose that the packaging accessory factor oligomerizes to concentrate positively charges in a central channel critical for packaging progression.

microbiology↗

bioRxiv2025

Mechanisms of HSV-1 helicase-primase inhibition and replication fork complex assembly

Herpesviruses are widespread double-stranded DNA viruses that establish lifelong latency and cause various diseases. Although DNA polymerase-targeting antivirals are effective, increasing drug resistance underscores the need for alternatives. Helicase-primase inhibitors (HPIs) are promising antivirals, but their mechanisms of action are poorly defined. Furthermore, how the helicase-primase (H/P) complex and DNA polymerase coordinate genome replication is not well understood for herpesviruses. Here, we report cryo-EM structures of the herpes simplex virus (HSV) H/P complex bound to HPIs, showing that these lock the helicase-primase complex in an inactive conformation. Single-molecule assays reveal that HPIs cause helicase-primase complexes to pause in unwinding activity on DNA. The structure of an HPI-bound replication fork complex, comprising the H/P complex (UL5, UL52, and UL8) and polymerase holoenzyme (UL30 and UL42), reveals a previously uncharacterized interface bridging these complexes. These findings provide a structural framework for understanding herpesvirus replisome assembly and advancing inhibitor development.

microbiology↗

bioRxiv2019

The HSV-1 immediate early protein ICP22 is a J-like protein required for Hsc70 reorganization during lytic infection

Molecular chaperones and co-chaperones are the most abundant cellular effectors of protein homeostasis, assisting protein folding and preventing aggregation of misfolded proteins. We have previously shown that HSV-1 infection results in the drastic spatial reorganization of the cellular chaperone Hsc70 into nuclear domains called VICE (Virus Induced Chaperone Enriched) domains and that this recruitment is dependent on the viral immediate early protein ICP22. In this paper, we present several lines of evidence supporting the notion that ICP22 functions as a virally encoded co-chaperone (J-protein/Hsp40) functioning together with its Hsc70 partner to recognize and manage aggregated and misfolded proteins. We show that ICP22 results in (i) nuclear sequestration of non-native proteins, (ii) reduction of cytoplasmic aggresomes in cells expressing aggregation-prone proteins and (iii) thermoprotection against heat-inactivation of firefly luciferase. (iv) Sequence homology analysis indicated that ICP22 contains an N-terminal J-domain and a C-terminal substrate binding domain, similar to type II cellular J-proteins. ICP22 may, thus, be functionally similar to J-protein/Hsp40 co-chaperones that function together with their HSP70 partners to prevent aggregation of non-native proteins. This is not the first example of a virus hijacking a function of a cellular chaperone, as SV40 T Antigen was previously shown to contain a J-domain; however, this the first known example of the acquisition of a complete J-like protein by a virus and suggests that HSV has taken advantage of the adaptable nature of J-proteins to evolve a multi-functional co-chaperone that functions with Hsc70 to promote lytic infection.\n\nIMPORTANCEViruses have evolved a variety of strategies to succeed in a hostile environment. The HSV immediate early protein ICP22 plays several roles in the virus life cycle including down-regulation of cellular gene expression, up-regulation of late viral gene expression, inhibition of apoptosis, prevention of aggregation of non-native proteins and the recruitment of a cellular heat shock protein, Hsc70, to nuclear domains. We present evidence that ICP22 resembles a cellular J-protein/HSP40 family co-chaperone, interacting specifically with Hsc70. This is the first known example of the acquisition of a complete J-like protein by a virus and suggests that HSV has evolved to manipulate the host proteostatic machinery during the establishment of lytic infection.

molecular biology↗