Biology subjects

Eppmann, S.

Publications and source records attributed to Eppmann, S..

3 recordsLinked to original sources

bioRxiv2026

Proteomics-Based Discovery of Symmetry-Specific Readers and Antireaders of 5-Formylcytosine in Mammalian DNA

5-methylcytosine (mC) and its oxidized derivatives are epigenetic modifications of mammalian DNA that play key roles in transcription, cell differentiation, and cancer. They predominantly occur within palindromic CpG dyads, creating multiple possible combinations across the two dyad strands, each representing a chemically distinct DNA major groove mark. Among the modifications, 5-formylcytosine (fC) interacts with a large number of proteins and has been associated with important roles in chromatin regulation. However, it is poorly understood whether nuclear proteins selectively recognize the symmetry of individual fC-containing CpG dyads. Here, we report the first proteome-wide interaction profiles of symmetric and asymmetric fC modifications in mammalian DNA. Our analysis spans several human and mouse cell lines and three DNA promoter probes containing CpG dyads with five distinct combinations of fC, C, and mC nucleobases. We identify a diverse set of fC reader proteins with distinct symmetry preferences, including transcription factors (e.g., MAX, HEY1, RFX5, SIX1, SIX2, and FOXJ3) and DNA repair proteins (MPG and TDG). Notably, some proteins act as fC readers or anti-readers depending on the sequence context, suggesting a role for fC in modulating their target selection. Our data reveal widespread symmetry-specific recognition of fC by mammalian proteins and provide a rich resource for studying its potential functions in chromatin regulation. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=183 HEIGHT=200 SRC="FIGDIR/small/717454v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@10773borg.highwire.dtl.DTLVardef@103ced4org.highwire.dtl.DTLVardef@fff20eorg.highwire.dtl.DTLVardef@16c9678_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2025

Mammalian Proteome Profiling Reveals Readers and Antireaders of Strand-Symmetric and -Asymmetric 5-Hydroxymethylcytosine-Modifications in DNA

The cytosine (C) modifications 5-methylcytosine (mC) and 5-hydroxymethylcytosine (hmC) are central regulatory elements of mammalian genomes. Both marks occur in dinucleotide contexts of double stranded DNA in either strand-symmetric or -asymmetric fashion, but it is still poorly understood how this symmetry information is selectively read out by the nuclear proteome as basis of potential symmetry-dependent regulation mechanisms. We report comparative enrichment/proteomics studies with promoter probes being strand-symmetrically or asymmetrically modified with C, mC and hmC, enabling a direct assessment of their reader profiles in the same sequence, tissue, and experimental contexts. We identify in human and mouse nuclear lysates a high number of tissue-specific readers for hmC-modified sequences that fall into distinct, probe-specific sub-groups, including members of important transcription factor classes and chromatin regulators. Among them, we discover the master regulators MYC and MAX that play central roles in cell (de)differentiation and cancer progression to read hmC in a sequence-dependent manner. We also find RFX5, a transcription factor critically involved in primary MHC class II deficiency to discriminate between specific hmC symmetries in CpG dyads. Our findings provide further support for the hypothesis that hmC symmetry information can provide distinct regulatory outputs, and provide a resource for studying the molecular mechanisms triggered by symmetric and asymmetric hmC modifications in chromatin regulation during development and disease.

biochemistry↗

bioRxiv2022

Epigenetic CpG Duplex Marks Probed by an Evolved DNA Reader via a Well-Tempered Conformational Plasticity

5-methylcytosine (mC) and its TET-oxidized derivatives exist in CpG dyads of mammalian DNA and regulate cell fate, but how their individual combinations in the two strands of a CpG act as distinct regulatory signals is poorly understood. Readers that selectively recognize such novel "CpG duplex marks" could be versatile tools for studying their biological functions, but their design represents an unprecedented selectivity challenge. By mutational studies, NMR relaxation, and MD simulations, we here show that the selectivity of the first designer reader for an oxidized CpG duplex mark hinges on precisely tempered conformational plasticity of the scaffold adopted during directed evolution. Our observations reveal the critical aspect of defined motional features in this novel reader for affinity and specificity in the DNA/protein interaction, providing unexpected prospects for further design progress in this novel area of DNA recognition.

genomics↗