Dissecting DNMT3B functions in immunodeficiency-centromeric instability facial anomalies syndrome

Mutations in the DNA methyltransferase DNMT3B cause the recessive genetic condition Immunodeficiency centromeric instability facial anomalies syndrome type 1 (ICF1). DNMTs deposit the repressive epigenetic mark DNA methylation on the genome. However, it is challenging to connect altered ICF1 DNA methylation patterns to disease phenotypes because DNMT3B recruitment is mediated by multiple pathways.

This project builds on our recent delineation of a pathway recruiting DNMT3B to constitutive heterochromatin (Taglini et al, 2024) to dissect the role of different DNMT3B functions in ICF1. We will generate human embryonic stem cell (hESC) lines with separation-of-function mutations targeting different DNMT3B recruitment pathways before characterising their epigenomes and transcriptomes compared to those with ICF1 mutations. As ICF1 is characterised by craniofacial phenotypes, we will also determine how these mutations impact differentiation of hESCs to cranial neural crest cells – a key cell type forming facial structures during development (Prescott et al, 2015; Long et al, 2020). This project lays the groundwork to understand the molecular basis of ICF1 patient phenotypes and ultimately design therapies. The major techniques used are: hESC culture, genome editing, Nanopore sequencing, CUT&Run, scRNA-seq and bioinformatics.

• Long et al 2020, https://doi.org/10.1016/j.stem.2020.09.001
• Prescott et al 2015, https://doi.org/10.1016/j.cell.2015.08.036
• Taglini et al 2024, https://doi.org/10.1038/s44319-024-00061-5