Biology subjects

Oberdoerffer, S.

Publications and source records attributed to Oberdoerffer, S..

5 recordsLinked to original sources

bioRxiv2026

EOLA1 functions in nucleotide salvage through deacetylating free N4-acetylcytidine

RNA-based medicines rely on modified nucleotides to promote immune evasion and in vivo efficacy. Nucleotides generated from RNA degradation are either exported or recycled through metabolically favorable salvage pathways, though whether modified nucleotides are efficiently recycled remains unclear. N4-acetylcytidine (acC) is a naturally occurring modification in rRNA and tRNA that has shown promise in therapeutic mRNA applications. However, N4-acetylation impairs cytidine deamination, the first step in cytidine salvage. Here, we investigate the endogenous mechanisms that enable acC metabolism. Through sensitive sequence and structural analyses, we identify the uncharacterized human ASCH domain protein EOLA1 as a key acC deacetylase in nucleotide salvage. EOLA1 inactivation leads to free intracellular acC accumulation and increased cytotoxicity upon nucleotide export inhibition. While steady-state acC levels in cellular RNAs remain unchanged, EOLA1-dependent regulation of free acC is evident basally and is exacerbated by exogenous mRNA delivery. Proteomic analyses place EOLA1 in proximity to ribosomal proteins, adjacent to endogenous acC sources. In vitro assays confirm EOLA1 specificity for acC, and structural analysis reveals a narrow nucleotide-binding pocket consistent with mononucleotide selectivity. These findings identify EOLA1 as a bona fide acC eraser and uncover a previously unrecognized pathway for recycling modified nucleotides with relevance to therapeutic RNA design.

molecular biology↗

bioRxiv2025

Peroxiredoxin 1 safeguards the nucleolar genome from oxidative damage

Peroxiredoxin 1 (PRDX1) is a highly conserved, thiol-dependent peroxidase that rapidly scavenges reactive oxygen species to modulate redox signaling. PRDX1-null mice exhibited genomic instability, shortened lifespan, and accelerated tumorigenesis, including development of lymphomas, sarcomas, and carcinomas. Despite extensive characterization of these phenotypes, the molecular mechanism by which PRDX1 loss causes genomic instability remains poorly understood. Here we show that PRDX1 deficiency alters nucleolar morphology, impairs RNA Polymerase I (POL-I)-dependent transcription of pre-ribosomal RNAs and triggers nucleolar genomic instability. This oxidative stress-induced nucleolar dysfunction promotes the stability of secondary DNA structures, such as RNA-DNA hybrids and G-quadruplex DNA, contributing to nucleolar genomic instability. We demonstrate that PRDX1 loss reduces nascent rRNA levels and impairs rRNA processing, further affecting ribosome biogenesis. Mechanistically, we established that PRDX1 loss triggers activation of the nucleolar DNA damage response including activation of DNA repair kinase ATM and the nucleolar factor TCOF1 within the nucleolus, and recruitment of the MRE11-RAD50-NBS1 (MRN) complex subunit NBS1 to ribosomal DNA (rDNA) loci. NBS1 accumulation correlates with the repression of rDNA transcription by POL-I, potentially delaying rRNA synthesis, and safeguarding the nucleolar genome from further oxidative damage. Collectively, these findings uncover a previously unrecognized, but critical role, for PRDX1 in maintaining nucleolar integrity and ribosomal biogenesis through redox-dependent regulation of rDNA transcription and processing machinery.

molecular biology↗

bioRxiv2018

Codon usage and amino acid identity are major determinants of mRNA stability in humans

mRNA degradation is a critical, yet poorly understood, aspect of gene expression. Previous studies demonstrate that codon content acts as a major determinant of mRNA stability in model organisms. In humans, the importance of open reading frame (ORF)-mediated regulation remains unclear. Here, we globally analyzed mRNA stability for both endogenous and human ORFeome collection mRNAs in human cells. Consistent with previous studies, we observed that synonymous codon usage impacts human mRNA decay. Unexpectedly, amino acid identity also acts as a driver of translation-dependent decay, meaning that primary protein sequence dictates overall mRNA levels and, consequently, protein abundance. Both codon usage and amino acid identity affect translational elongation rate to varying degrees in distinct organisms, with the net result being sensed by mRNA degradation machinery. In humans, interplay between ORF- and UTR-mediated control of mRNA stability may be critical to offset this fundamental relationship between protein sequence and mRNA abundance.

molecular biology↗

bioRxiv2018

TET-catalyzed 5-carboxylcytosine promotes CTCF binding to suboptimal sequences genome-wide

The mechanisms supporting dynamic regulation of CTCF binding sites remain poorly understood. Here we describe the TET-catalyzed 5-methylcytosine derivative, 5-carboxylcytosine (5caC) as a factor driving new CTCF binding within genomic DNA. Through a combination of in vivo and in vitro approaches, we reveal that 5caC generally strengthens CTCF association with DNA and facilitates binding to suboptimal sequences. Dramatically, profiling of CTCF binding in a cellular model that accumulates genomic 5caC identified [~]13,000 new CTCF sites. The new sites were enriched for overlapping 5caC and were marked by an overall reduction in CTCF motif strength. As CTCF has multiple roles in gene expression, these findings have wide-reaching implications and point to induced 5caC as a potential mechanism to achieve differential CTCF binding in cells.

molecular biology↗

bioRxiv2017

Independence Between Pre-mRNA Splicing And De Novo DNA Methylation In An Isogenic Minigene Resource

Actively transcribed genes adopt a unique chromatin environment with characteristic patterns of enrichment. Within gene bodies, H3K36me3 and cytosine DNA methylation are elevated at exons of spliced genes and have been implicated in the regulation of pre-mRNA splicing. H3K36me3 is further responsive to splicing, wherein splicing inhibition led to a redistribution and general reduction over gene bodies. In contrast, little is known of the mechanisms supporting elevated DNA methylation at actively spliced genic locations. Recent evidence associating the de novo DNA methyltransferase Dnmt3b with H3K36me3-rich chromatin raises the possibility that genic DNA methylation is influenced by splicing-associated H3K36me3. Here, we report the generation of an isogenic resource to test the direct impact of splicing on chromatin. A panel of minigenes of varying splicing potential were integrated into a single FRT site for inducible expression. Profiling of H3K36me3 confirmed the established relationship to splicing, wherein levels were directly correlated with splicing efficiency. In contrast, DNA methylation was equivalently detected across the minigene panel, irrespective of splicing and H3K36me3 status. In addition to revealing a degree of independence between genic H3K36me3 and DNA methylation, these findings highlight the generated minigene panel as a flexible platform for the query of splicing-dependent chromatin modifications.

molecular biology↗