Project description:In this study, we investigated the dynamics during differentiation of the in vivo binding sites of ZBTB2, a putative reader for unmethylated DNA. We performed DNA pull-downs followed by mass spectrometry, using a genomic sequence containing either unmethylated or methylated CpGs, to study the influence of DNA methylation on ZBTB2 binding. Additionally, we performed interaction proteomics to identify ZBTB2 interaction partners. We found that ZBTB2 recruits a zinc finger module of three proteins to unmethylated DNA.
Project description:DNA methylation is a dynamic epigenetic modification that plays a key role in various cellular processes. Proteins that bind to DNA depending on its methylation status are thought to play an important role in DNA methylation-mediated gene expression. Using a variety of genomics and proteomics approaches, we identified ZBTB2 as a novel reader of unmethylated DNA. ZBTB2, which forms a complex with ZBTB25 and ZNF639, preferentially binds at CpG island promoters in mouse embryonic stem cells, from where it regulates genes that are involved in the exit from pluripotency. Binding of ZBTB2 to target genes is mostly associated with gene activation. Furthermore, ZBTB2 is intricately interwoven with DNA methylation, as we found not only that its binding to DNA is methylation-sensitive, but also that ZBTB2 regulates the turnover of methylated DNA. Summarising, we propose that ZBTB2 is a DNA methylation-sensitive transcription factor that is involved in cellular differentiation.
Project description:DNA methylation is a dynamic epigenetic modification that plays a key role in various cellular processes. Proteins that bind to DNA depending on its methylation status are thought to play an important role in DNA methylation-mediated gene expression. Using a variety of genomics and proteomics approaches, we identified ZBTB2 as a novel reader of unmethylated DNA. ZBTB2, which forms a complex with ZBTB25 and ZNF639, preferentially binds at CpG island promoters in mouse embryonic stem cells, from where it regulates genes that are involved in the exit from pluripotency. Binding of ZBTB2 to target genes is mostly associated with gene activation. Furthermore, ZBTB2 is intricately interwoven with DNA methylation, as we found not only that its binding to DNA is methylation-sensitive, but also that ZBTB2 regulates the turnover of methylated DNA. Summarising, we propose that ZBTB2 is a DNA methylation-sensitive transcription factor that is involved in cellular differentiation.
Project description:CpG-islands (CGIs) are key regulatory DNA elements at most promoters, but how they influence the chromatin status and transcription remains elusive. Here we identify and characterize SAMD1 (SAM domain-containing protein 1) as an unmethylated CGI-binding protein. SAMD1 possesses an atypical winged-helix domain that directly recognizes unmethylated CpG-containing DNA via simultaneous interactions with both the major and the minor groove. The SAM domain interacts with L3MBTL3, but it can also homopolymerize into a closed pentameric ring. At a genome-wide level, SAMD1 localizes to H3K4me3-decorated CGIs, where it acts as a repressor. SAMD1 tethers L3MBTL3 to chromatin and interacts with the KDM1A histone demethylase complex to modulate H3K4me2 and H3K4me3 levels at CGIs, thereby providing a mechanism for SAMD1-mediated transcriptional repression. Absence of SAMD1 impairs ES cell differentiation processes, leading to mis-regulation of key biological pathways. Together, our work establishes SAMD1 as a novel chromatin regulator acting at unmethylated CGIs.
Project description:The lysine acetyltransferase KAT6A (MOZ, MYST3) belongs to the MYST family of chromatin regulators, facilitating histone acetylation. Dysregulation of KAT6A has been implicated in developmental syndromes and the onset of acute myeloid leukemia (AML). Previous work suggests that KAT6A is recruited to its genomic targets by a combinatorial function of histone binding PHD fingers, transcription factors and chromatin binding interaction partners. Here, we demonstrated that a winged helix domain at the N-terminus of KAT6A specifically interacts with unmethylated CpG motifs. This DNA binding function leads to the association of KAT6A to unmethylated CpG islands (CGIs) genome wide. Mutation of the essential amino acids completely abrogates the enrichment of KAT6A at CGIs. Overexpression of a KAT6A WH1 mutant has a dominant negative effect on H3K9 histone acetylation, which is comparable to the effects upon overexpression of a KAT6A HAT domain mutant. Taken together, our work revealed a previously unrecognized chromatin recruitment mechanism of KAT6A, offering a new perspective on the role of KAT6A in gene regulation and human diseases
Project description:CpG-islands (CGIs) are key regulatory DNA elements at most promoters, but how they influence the chromatin status and transcription remains elusive. Here we identify and characterize SAMD1 (SAM domain-containing protein 1) as an unmethylated CGI-binding protein. SAMD1 possesses an atypical winged-helix domain that directly recognizes unmethylated CpG-containing DNA via simultaneous interactions with both the major and the minor groove. The SAM domain interacts with L3MBTL3, but it can also homopolymerize into a closed pentameric ring. At a genome-wide level, SAMD1 localizes to H3K4me3-decorated CGIs, where it acts as a repressor. SAMD1 tethers L3MBTL3 to chromatin and interacts with the KDM1A histone demethylase complex to modulate H3K4me2 and H3K4me3 levels at CGIs, thereby providing a mechanism for SAMD1-mediated transcriptional repression. Absence of SAMD1 impairs ES cell differentiation processes, leading to miss-regulation of key biological pathways. Together, our work establishes SAMD1 as a novel chromatin regulator acting at unmethylated CGIs.