Single molecule dynamics of transcription factors driving human embryonic stem cell differentiation
Development and differentiation involve massive and often rapid changes in transcription activity, chromatin landscape as well as the nuclear architecture. During these processes, lineage-specific transcription factors are believed to play crucial roles in driving lineage-specific transcription programs and determining cell fates. The human embryonic stem cell (hESC) and in vitro differentiation provide us a proximal system to study the dynamic changes and regulation mechanisms in human early development. I set up an experimental system for tracking endogenous factors at single molecule resolution in hESC and hESC differentiating to definitive endoderm, taking advantage of CRISPR/Cas9 mediated genome editing and single molecule imaging. This allows us to characterize the diffusing and binding properties of lineage-specific transcription factors in live cells while they are functioning in the hESC that undergoes lineage commitment. Combined with other microscopic methods and genomic methods, single molecule tracking provides a glimpse of how transcription factors engage with their targets in the context of chromatin and promote cell fate transition.