Biology subjects

Elroy-Stein, O.

Publications and source records attributed to Elroy-Stein, O..

4 recordsLinked to original sources

bioRxiv2025

Repurposed hnRNPC binds mature mRNAs and safeguards the mitotic transcriptome

Upon entry to mitosis, RNA metabolism is broadly suppressed. While mechanistic understanding is limited, the mitotic transcriptome is known to be generally preserved to allow the daughter cells an economical and efficient start. We used highly effective cell cycle synchronization to specifically characterize mitotic hnRNPC, an abundant nuclear RNA-binding protein known for intron binding and splicing regulation during interphase. Two density-distinct hnRNPC-RNP populations (low-and high-density; LD and HD) were identified in mitotic cells. RNA-seq analysis combined with fluorescent Cross Linking and Immuno-Precipitation (fCLIP) revealed hnRNPC binding to 17.1% and 8.7% of expressed genes in LD- and HD-complexes, respectively, with most sites mapping to protein-coding genes (77% and 68%, respectively). Mediated by its known cooperative interaction with U-rich motifs, mitotic hnRNPC acquired prevalent interactions with exons, predominantly within the 3 untranslated region of mature mRNAs. Mitotic hnRNPC also retained intron interactions, predominantly in LD-hnRNPC RNPs, which comigrated with both the spliceosome and mono-ribosomes through a density gradient. Interestingly, LD-hnRNPC also interacted with mature mRNAs characterized by short coding sequences, in agreement with mono-ribosome loading. Conversely, HD-hnRNPC, which co-migrated with poly-ribosomes, predominantly interacted with mature mRNA complexes. Downregulation of hnRNPC elicited a global negative effect on the abundance of its mitotic targets. The data points to the global role of mitotic hnRNPC as a stabilizer of pre-mRNA and mRNA. Future studies should provide additional insights related to its multifunctional roles during mitosis.

cell biology↗

bioRxiv2025

The Translational Landscape of Reactive Astrocytes Reveals the Impact of eIF2B-mediated Dysregulation in VWM Disease

A devastating genetic recessive neurodegenerative disorder, Vanishing White Matter Disease (VWMD), stems from mutations in eIF2B--a master regulator of mRNA translation initiation and mediator of cellular stress response. While astrocytes, the brains essential support cells, are known to be central to VWMD pathology, the molecular mechanisms underlying their dysfunction remain poorly understood. Our study reveals that even a mild mutation in eIF2B5 profoundly disrupts astrocyte mRNA translation regulation upon cytokine-mediated activation, affecting nearly one-third of all expressed genes. Through innovative integration of RNA-seq and Ribo-seq analyses using primary cell cultures of astrocytes isolated from eIF2B5R132H/R132H mice, we discovered attempts to compensate for impaired protein production by increasing mRNA levels. However, this compensation proves insufficient to maintain critical cellular functions. Our comprehensive analysis uncovered significant disruptions in cellular energy production and protein synthesis machinery. We also predicted previously unknown defects in cholesterol biosynthesis within mutant astrocytes. Moreover, a meta-analysis of translation initiation scores pinpointed, for the first time, a short list of specific effector gene candidates that may drive disease progression. This powerful combination of transcriptome and translatome illuminates the complex pathophysiology of VWMD and identifies promising new biomarkers and therapeutic target opportunities.

molecular biology↗

bioRxiv2022

mTOR pathway inhibition stimulates pharmacologically induced nonsense suppression

A large number of human genetic diseases result from premature termination codons (PTCs) caused by splicing defects, insertions, deletions or point mutations also termed nonsense mutations. Nonsense mutations are the source of various genetic diseases, ranging from rare neuro-metabolic disorders to relatively common inheritable cancer syndromes and muscular dystrophies. Over the years, a wide spectrum of studies has shown that certain antibiotics and other synthetic molecules can act as nonsense mutation suppressors, by inducing readthrough of the stop-codon leading to the expression of a full-length protein. Unfortunately, most readthrough-inducing agents have limited effects and are toxic. Thus, efforts are made to improve the clinical outcome of nonsense mutation suppressors. Here we show that the mTOR pathway is involved in antibiotic-mediated readthrough of nonsense mutations at the level of protein translation initiation. We demonstrate that inhibition of the mTOR translation-initiation-controlling eIF4E branch induces antibiotic-mediated nonsense mutation readthrough, paving the way to the development of a novel therapeutic strategy for enhancing the restoration of these disease-causing mutated transcripts.

cell biology↗

bioRxiv2020

Leukodystrophy resembling Vanishing White Matter Disease is recapitulated by brain-specific depletion of apoptosis regulator MCL-1

Neurologic disorders often disproportionately affect specific brain regions, and different apoptotic mechanisms may contribute to white matter pathology in leukodystrophies or gray matter pathology in poliodystrophies. We previously showed that neural progenitors that generate cerebellar gray matter depend on the anti-apoptotic protein BCL-xL. Conditional deletion of Bcl-xL in these progenitors produces spontaneous apoptosis and cerebellar hypoplasia, while similar conditional deletion of Mcl-1 produces no phenotype. Here, we show that, in contrast, postnatal oligodendrocytes depend on MCL-1. We found that brain-wide Mcl-1 deletion caused apoptosis specifically in mature oligodendrocytes while sparing astrocytes and oligodendrocyte precursors, resulting in impaired myelination and progressive white matter degeneration. Disabling apoptosis through co-deletion of Bax or Bak rescued white matter degeneration, implicating the intrinsic apoptotic pathway in Mcl-1-dependence. Bax and Bak co-deletions rescued different aspects of the Mcl-1-deleted phenotype, demonstrating their discrete roles in white matter stability. MCL-1 protein abundance was reduced in eif2b5-mutant mouse model of the leukodystrophy vanishing white matter disease (VWMD), suggesting the potential for MCL-1 deficiency to contribute to clinical neurologic disease. Our data show that oligodendrocytes require MCL-1 to suppress apoptosis, implicate MCL-1 deficiency in white matter pathology, and suggest apoptosis inhibition as a leukodystrophy therapy.

neuroscience↗