Biology subjects

Spangle, J. M.

Publications and source records attributed to Spangle, J. M..

5 recordsLinked to original sources

bioRxiv2026

Overexpression of Eaf1, a subunit of the NuA4 lysine acetyl transferase complex, rescues growth defects in the budding yeast H3K36M oncohistone model via histone H4 tail acetylation

Histone proteins are critical for regulating nucleic acid transactions, including gene expression. Specific missense mutations in histone genes have been linked to oncogenesis, creating oncohistones. One of the first identified oncohistones converts K36 in histone H3 to M (H3K36M). While humans have 15 H3 genes, the Saccharomyces cerevisiae genome contains only two H3 genes. As H3 shares 90% sequence identity between budding yeast and humans, the budding yeast system provides an ideal model for study of H3K36M. We previously identified the catalytic subunit of the NuA4 lysine acetyltransferase complex as a high copy suppressor of growth defects in H3K36 mutant yeast cells. Here, we demonstrate that the NuA4 scaffold Eaf1 suppresses mutant H3K36 growth defects. We show that this suppression by Eaf1 is dependent on the Eaf1 HSA domain. To examine whether the role of NuA4 in acetylating histone H4 is required for suppression of H3K36 growth defects, we altered the four NuA4 target lysines within H4 (K5, 8, 12, and 16) to create quadruple histone mutants with all four of these lysines converted to alanine (H4-4K[->]A) or arginine (H4-4K[->]R). These H4 mutants have reduced viability and disrupted global H4 acetylation. Eaf1 cannot suppress growth defects in these H4 acetylation mutants, suggesting Eaf1-mediated suppression is dependent on acetylation of H4 N-terminal tails. We further show that inhibiting NuA4 activity in H3K36M human cells limits their oncogenic potential. Together, this work defines a mechanistic connection between H3K36 and H4 N-terminal tail acetylation in the context of a cancer-causing mutation. Article SummarySpecific mutations in histone genes have been found to cause various cancers, creating oncohistones, and the exact mechanisms by which they drive oncogenesis remain to be characterized. Budding yeast is a simple yet powerful model for studying oncohistones such as H3K36M. Subunits of the NuA4 lysine acetyltransferase complex were found to suppress growth defects in budding yeast expressing H3K36M. This suppression was dependent on the presence of the NuA4 target lysines in histone H4. Additionally, inhibiting NuA4 activity in human H3K36M cells limited their oncogenic potential. This work characterizes the mechanistic relationship between H3K36M and the NuA4 complex.

genetics↗

bioRxiv2025

Lead (Pb) exposure alters neural cell fate in the developing human brain

The heavy metal lead (Pb) is a developmental neurotoxicant associated with cognitive and behavioral deficits, but the cellular mechanisms underlying these impairments remain unclear. Here we show that prenatal Pb exposure biases human radial glia fate, prolonging neurogenesis and suppressing astrogenesis. We used hiPSC-derived cortical organoids, primary human fetal tissue, and in vivo xenografts to demonstrate that Pb exposure alters radial glial differentiation. Pb-exposed organoids contain a higher proportion of neurons and fewer astrocytes. We validated this differentiation bias in primary radial glia from human cortices (GW16-20), observing Pb-associated reductions in astrocyte commitment via genetic lineage tracing. This correlated with increased H3K27me3, a repressive histone modification deposited by the histone methyltransferase complex PRC2, suggesting epigenetic reprogramming as a mechanistic link between Pb and neural cell fate commitment. Our findings indicate that prenatal Pb exposure impacts lineage commitment in the developing brain, which may contribute to cognitive and behavioral impairment.

neuroscience↗

bioRxiv2023

Histone H3 E50K mutation confers oncogenic activity and supports an EMT phenotype

Sequencing of human patient tumors has identified recurrent missense mutations in genes encoding core histones. We report that mutations that convert histone H3 amino acid 50 from a glutamate to a lysine (H3E50K) support an oncogenic phenotype in human cells. Expression of H3E50K is sufficient to transform human cells as evidenced by a dramatic increase in cell migration and invasion, and a statistically significant increase in proliferation and clonogenicity. H3E50K also increases the invasive phenotype in the context of co-occurring BRAF mutations, which are present in patient tumors characterized by H3E50K. H3E50 lies on the globular domain surface in a region that contacts H4 within the nucleosome. We find that H3E50K perturbs proximal H3 post-translational modifications globally and dysregulates gene expression, activating the epithelial to mesenchymal transition. Functional studies using S. cerevisiae reveal that, while yeast cells that express H3E50K as the sole copy of histone H3 show sensitivity to cellular stressors, including caffeine, H3E50K cells display some genetic interactions that are distinct from the characterized H3K36M oncohistone yeast model. Taken together, these data suggest that additional histone H3 mutations have the potential to be oncogenic drivers and function through distinct mechanisms that dysregulate gene expression. SummaryO_LIRecurrent missense mutation that alter histone H3E50 were identified in patient tumors C_LIO_LIH3E50K expression dysregulates global H3 post-translational modification, gene expression and may govern a transcriptional program associated with metastatic phenotypes C_LIO_LIhht2-E50K yeast cells exhibit growth defects in the presence of DNA damaging agents C_LI

cancer biology↗

bioRxiv2022

Targeting TRIP13 in Wilms Tumor with Nuclear Export Inhibitors

Wilms tumor (WT) is the most common renal malignancy of childhood. Despite improvements in the overall survival, relapse occurs in ~15% of patients with favorable histology WT (FHWT). Half of these patients will succumb to their disease. Identifying novel targeted therapies in a systematic manner remains challenging in part due to the lack of faithful preclinical in vitro models. We established ten short-term patient-derived WT cell lines and characterized these models using low-coverage whole genome sequencing, whole exome sequencing and RNA-sequencing, which demonstrated that these ex-vivo models faithfully recapitulate WT biology. We then performed targeted RNAi and CRISPR-Cas9 loss-of-function screens and identified the nuclear export genes (XPO1 and KPNB1) as strong vulnerabilities. We observed that these models are sensitive to nuclear export inhibition using the FDA approved therapeutic agent, selinexor (KPT-330). Selinexor treatment of FHWT suppressed TRIP13 expression, which was required for survival. We further identified in vitro and in vivo synergy between selinexor and doxorubicin, a chemotherapy used in high risk FHWT. Taken together, we identified XPO1 inhibition with selinexor as a potential therapeutic option to treat FHWTs and in combination with doxorubicin, leads to durable remissions in vivo.

cancer biology↗

bioRxiv2021

A Budding Yeast Model and Screen to Define the Functional Consequences of Oncogenic Histone Missense Mutations

Somatic missense mutations in histone genes turn these essential proteins into oncohistones, which can drive oncogenesis. Understanding how missense mutations alter histone function is challenging in mammals as mutations occur in a single histone gene. For example, described oncohistone mutations predominantly occur in the histone H3.3 gene, despite the human genome encoding 15 H3 genes. To understand how oncogenic histone missense mutations alter histone function, we leveraged the budding yeast model, which contains only two H3 genes, to explore the functional consequences of oncohistones H3K36M, H3G34W, H3G34L, H3G34R, and H3G34V. Analysis of cells that express each of these variants as the sole copy of H3 reveals that H3K36 mutants show different drug sensitivities compared to H3G34 mutants. This finding suggests that changes to proximal amino acids in the H3 N-terminal tail alter distinct biological pathways. We exploited the caffeine sensitive growth of H3K36 mutant cells to perform a high copy suppressor screen. This screen identified genes linked to histone function and transcriptional regulation, including Esa1, a histone H4/H2A acetyltransferase; Tos4, a forkhead-associated domain-containing gene expression regulator; Pho92, an N6-methyladenosine RNA binding protein and Sgv1/Bur1, a cyclin-dependent kinase. We show that the Esa1 lysine acetyltransferase activity is critical for suppression of the caffeine sensitive growth of H3K36R mutant cells while the previously characterized binding interactions of Tos4 and Pho92 are not required for suppression. This screen identifies pathways that could be altered by oncohistone mutations and highlights the value of yeast genetics to identify pathways altered by such mutations.

genetics↗