C9orf72 expansion creates the unstable folate-sensitive fragile site FRA9A

Mirceta, M.; Schmidt, M. H. M.; Shum, N.; Prasolava, T. K.; Meikle, B.; Lanni, S.; Mohiuddin, M.; Mckeever, P. M.; Zhang, M.; Liang, M.; van der Werf, I.; Scheers, S.; Dion, P. A.; Wang, P.; Wilson, M. D.; Abell, T.; Philips, E. A.; Sznajder, L. J.; Swanson, M. S.; Mehkary, M.; Khan, M.; Yokoi, K.; Jung, C.; de Jong, P. J.; Freudenreich, C. H.; McGoldrick, P.; Yuen, R. K. C.; Abrahao, A.; Keith, J.; Zinman, L.; Robertson, J.; Rogaeva, E.; Rouleau, G. A.; Kooy, R. F.; Pearson, C. E.

doi:10.1101/2024.10.26.620312

Home/Archive/bioRxiv

bioRxiv · 10.1101/2024.10.26.620312

C9orf72 expansion creates the unstable folate-sensitive fragile site FRA9A

View original source ↗Export metadata ↓

Abstract

The hyper-unstable Chr9p21 locus, harbouring the interferon gene cluster, oncogenes and C9orf72, is linked to multiple diseases. C9orf72 (GGGGCC)n expansions (C9orf72Exp) are associated with incompletely penetrant amyotrophic lateral sclerosis, frontotemporal dementia and autoimmune disorders. C9orf72Exp patients display hyperactive cGAS-STING-linked interferon immune and DNA damage responses, but the source of immuno-stimulatory or damaged DNA is unknown. Here, we show C9orf72Exp in pre-symptomatic and ALS-FTD patient cells and brains cause the folate- sensitive chromosomal fragile site, FRA9A. FRA9A centers on >33kb of C9orf72 as highly-compacted chromatin embedded in an 8.2Mb fragility zone spanning 9p21, encompassing 46 genes, making FRA9A one of the largest fragile sites. C9orf72Exp cells show chromosomal instability, heightened global- and Chr9p-enriched sister-chromatid exchanges, truncated-Chr9s, acentric-Chr9s and Chr9-containing micronuclei, providing endogenous sources of damaged and immunostimulatory DNA. Cells from one C9orf72Exp patient contained highly-rearranged FRA9A-expressing Chr9 with Chr9-wide dysregulated gene expression. Somatic C9orf72Exp repeat instability and chromosomal fragility are sensitive to folate-deficiency. Age-dependent repeat instability, chromosomal fragility, and chromosomal instability can be transferred to CNS and peripheral tissues of transgenic C9orf72Exp mice, implicating C9orf72Exp as the source. Our results highlight unappreciated effects of C9orf72 expansions that trigger vitamin-sensitive chromosome fragility, adding structural variations to the disease-enriched 9p21 locus, and likely elsewhere. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=94 SRC="FIGDIR/small/620312v2_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@154b23borg.highwire.dtl.DTLVardef@1814a6dorg.highwire.dtl.DTLVardef@13d713eorg.highwire.dtl.DTLVardef@d5d994_HPS_FORMAT_FIGEXP M_FIG C_FIG

Explore related subjects

genetics Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Mirceta, M., Schmidt, M. H. M., Shum, N., Prasolava, T. K., Meikle, B., Lanni, S., Mohiuddin, M., Mckeever, P. M., Zhang, M., Liang, M., van der Werf, I., Scheers, S., Dion, P. A., Wang, P., Wilson, M. D., Abell, T., Philips, E. A., Sznajder, L. J., Swanson, M. S., Mehkary, M., Khan, M., Yokoi, K., Jung, C., de Jong, P. J., Freudenreich, C. H., McGoldrick, P., Yuen, R. K. C., Abrahao, A., Keith, J., Zinman, L., Robertson, J., Rogaeva, E., Rouleau, G. A., Kooy, R. F., Pearson, C. E.. 2024-10-29. C9orf72 expansion creates the unstable folate-sensitive fragile site FRA9A. https://doi.org/10.1101/2024.10.26.620312

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

A largely shared genetic architecture underlies Saccharomyces cerevisiae persistence across different mouse host genotypes

The extent to which interactions between microbial and host genotypes shape opportunistic pathogen persistence within hosts is an important open question. To assess the contribution of these interactions to persistence, we used Saccharomyces cerevisiae , a genetically tractable model for studying opportunistic fungal persistence in mammalian hosts. A pooled panel of barcoded haploid segregants from a cross between a laboratory strain and a clinical isolate, together with both parents, was introduced intravenously into seven genetically diverse mouse strains. We measured the relative persistence of segregants in mouse brains and livers using barcode sequencing. Persistence showed transgressive segregation in both organs. On average across the two organs, yeast genotype explained 45.2% of the variance in segregant persistence, whereas yeast genotype-by-host genotype interactions explained only 2.9%. Linkage mapping showed that loci detected in more host genotypes generally explained more phenotypic variance than those detected in fewer host genotypes. At some loci, genetic variation correlated with increased yeast persistence across multiple organs (general loci) while at others increased persistence in one organ came at the cost of decreased persistence in another (antagonistic loci). General loci contributed disproportionately to brain persistence, whereas liver persistence reflected contributions from both classes. The clinical parent showed greater persistence than the laboratory parent in every host-organ combination, and the additive effects of detected loci predicted the direction of this advantage. Overall, this work shows that in this system, relative microbial persistence is polygenic, with a strong additive component and only a very small contribution from microbial genotype-by-host genotype interactions.

genetics↗

bioRxiv2026

Host control and regulation of human anellovirus persistence

Anelloviruses are the most abundant and diverse eukaryotic viruses known to infect humans and can persist throughout our lifetimes. Despite their ubiquity, the host factors governing their physiologic distribution and abundance remain poorly understood. Here, we construct a viral pangenome of 2,023 strains to quantify anellovirus DNA in >1.1 million participants spanning three genetic biobanks. Genome-wide association studies identify 121 loci linked to viral persistence, predominantly via immune regulation by NF-kB signaling. Further, we associate variable anellovirus detection with conditions characterized by immune dysfunction, including lymphoid malignancies. By screening 3.2 petabases of human single-cell sequencing data, we identify myeloid progenitors in the bone marrow as a prominent site of anellovirus transcription in vivo. Finally, Perturb-seq of anellovirus proteins reveals that anellovirus ORF2, particularly from Alphatorquevirus, attenuates TNF-a-induced NF-kB signaling, connecting host genetic variation, cellular context, and viral immunomodulation to characterize the persistence of the eukaryotic human virome's most abundant component.

genetics↗

bioRxiv2026

Regulation of sociality and neuronal development by the translation initiation factor eIF4H1 in Drosophila

Most animal species exhibit some level of sociality. However, whether sociality-related traits evolved independently, or are instead derived from common core mechanisms, remains controversial. Nevertheless, an emerging theoretical framework stipulates that key aspects of how animals interact with their social environments may be regulated by a phylogenetically conserved genetic toolkit. Therefore, we hypothesized that mutations that lead to social deficits in specific human disorders may implicate genes that play conserved roles in the regulation of core social traits across Animalia. Specifically, here we focus on genes associated with Williams syndrome (WS), a rare human multi-system disorder characterized in part by hypersocial cognitive traits. WS is caused by a hemizygous chromosomal microdeletion of 25-28 protein-coding genes. Consequently, it has been hypothesized that haploinsufficiency in at least one of these genes plays an important role in the development and/or function of social neural circuits in humans. Because the Drosophila genome encodes orthologs of 17 of the 28 genes deleted in WS, we reasoned that at least some of them may serve a conserved role in the regulation of social traits across flies and humans, as predicted by the genetic toolkit framework. Using a neuron-specific RNAi knockdown screen, we identified eIF4H1, an ortholog of a highly conserved subunit of the eukaryotic translation initiation complex eIF4F, as a candidate gene for neuronal regulation of sociality in the fly. We show that eIF4H1 expression is predominantly neuronal in the adult fly brain, and that its action plays a differential role in the organization of specific dopaminergic neuron subtypes that are associated with sociality and cognitive functions. These results indicate that eIF4H1 may serve a conserved function in regulating the development of the neuronal circuits that regulate social behaviors, thus supporting the idea of a conserved sociality genetic toolkit.

genetics↗