Role of ALKBH1 in the Core Transcriptional Network of Embryonic Stem Cells

Abstract

Background/Aims: ALKBH1, an AlkB homologue in the 2-oxoglutarate and Fe²⁺ dependent hydroxylase family, is a histone dioxygenase that removes methyl groups from histone H2A. Studies of transgenic mice lacking Alkbh1 reveal that most Alkbh1^-/- embryos die during embryonic development. Embryonic stem cells (ESCs) derived from these mice have prolonged expression of pluripotency markers and delayed induction of genes involved in neural differentiation, indicating that ALKBH1 is involved in regulation of pluripotency and differentiation. The aim of this study was to further investigate the role ALKBH1 in early development. Methods: Double-filter methods for nitrocellulose-filter binding, dot blot, enzyme-linked immunosorbent assay (ELISA), immonocytochemistry, cell culture and differentiation of mouse ESCs, Co-IP and miRNA analysis. Results: We found that SOX2 and NANOG bind the ALKBH1 promoter, and we identified protein-protein interactions between ALKBH1 and these core transcription factors of the pluripotency network. Furthermore, lack of ALKBH1 affected the expression of developmentally important miRNAs, which are involved in the regulation of NANOG, SOX2 and neural differentiation. Conclusion: Our results suggest that ALKBH1 interacts with the core transcriptional pluripotency network of ESCs and is involved in regulation of pluripotency and differentiation.

NSUN 3 and ABH 1 modify the wobble position of mt‐t RNA Met to expand codon recognition in mitochondrial translation

“…Interestingly, previous reports have suggested a differential localisation of ABH1 in different cell types. While the dioxygenase is mainly localised in mitochondria and the cytoplasm in HEK293 and HeLa cells ( Fig 5; Westbye et al, 2008), it has been reported to be nuclear in embryonic stem cells (Ougland et al, 2012(Ougland et al, , 2016. Together, these findings suggest that the methylation of cytosine 34 in mt-tRNA Met by NSUN3 represents an important modification present in many, if not all cell types, while the different localisation of ABH1 might result in differential modification of mt-tRNA Met on cytosine 34 in different cell types, tissues and developmental stages and might thereby fine tune mitochondrial translation in vivo.…”

Human and Arabidopsis alpha‐ketoglutarate‐dependent dioxygenase homolog proteins—New players in important regulatory processes

“…Depending on the species, particular ALKBH proteins show diverse cellular localization, substrate specificity, and the ability to interact with other proteins . Here, we compare functions of ALKBH proteins present in higher eukaryotes of distinct taxons—mammals, especially H. sapiens and higher plant like A. thaliana .…”

“…It also influences translation by mediating the demethylation of 1‐meA on tRNA . Finally, ALKBH1 interacts with transcription factors of pluripotency and is involved in its regulation and differentiation . Other studies indicate that ALKBH1 protein, independent of dioxygenase domain, possesses DNA lyase activity .…”

“…Such residues are important epigenetic markers, influencing expression of other proteins, affecting overall cellular metabolism, which are further discussed on the example of FTO and ALKBH5 proteins in Section 3. It cannot be excluded that other proteins may influence enzymatic activity of ALKBH through direct protein–protein interaction, like in the case of ALKBH1 or by introducing posttranslational modification (PTM)—e.g., FTO . Thus, the ALKBH protein family is a great example of “protein moonlighting,” a phenomenon in which a single protein may perform a number of different unrelated functions …”

SC1 Promotes MiR124-3p Expression to Maintain the Self-Renewal of Mouse Embryonic Stem Cells by Inhibiting the MEK/ERK Pathway

“…Cultured ES cells have three characteristics in vitro : self-renewal, pluripotency and limitless proliferation [3, 4]. The self-renewal of mouse ES cells maintained by activating pluripotent-related signalling pathways or inhibiting differentiation-related signalling pathways [5-7]. Some small molecule modulators maintain the undifferentiated and pluripotent state of mouse ES cells by affecting different signalling pathways.…”