(405d) Novel Probe to Monitor Histone Modification during Neuron Differentiation

Epigenetics, including DNA methylation, histone modification and noncoding RNA action, is the study of the molecular mechanisms that regulate gene expression without changing the DNA sequence and thus acts as the bridge between genotype and phenotype. H4K20me3 is a histone modification enriched in heterochromatin that functions in transcriptional silencing, genome stability and cell differentiation, and has been indicated to coordinate with DNA methylation during these biological processes. In mammals, DNA methylation is maintained by DNA methyltransferase 1 (DNMT1), the genetic mutation of which has been identified in patients with neurodegenerative diseases. Although interaction between DNMT1 and H4K20me3 has been illustrated to reinforce DNA methylation, how it contributes to development deficits of DNMT1 mutation-carrying patients remains unclear. To fill this gap, we developed a novel probe that specifically targets H4K20me3 and demonstrated its capability for high-specificity targeting in single-cell level, and validated its feasibility to study interaction between H4K20me3 and DNA methylation via co-transfection with our previously developed DNA methylation probe. We then delivered it into human induced pluripotent stem cells(iPSCs) carrying DNMT1-Y511C mutation as well as mature cortical neurons differentiated from mutation-carrying iPSCs, and tracked H4K20me3 spatial distribution during various differentiation stages. Our tool offers a unique opportunity to trace H4K20me3 distribution dynamics during differentiation and investigate its critical role in the onset of neurodegenerative diseases.