Expression profiling by high throughput sequencing Genome binding/occupancy profiling by high throughput sequencing
Summary
Cell density affects numerous biological processes, including gene expression and cell fate specification. However, mechanistic understanding of how changes in cell density alter the transcriptome is lacking. Here, we reveal that the expression of thousands of genes in mouse embryonic stem cells is affected by cell density. Furthermore, we find that low cell density enhances the efficiency of differentiation. Mechanistically, β-catenin is localized primarily to adherens junctions during conditions of high cell-cell contact. At low seeding density during differentiation, we observe that β-catenin translocates to the nucleus and co-activates target genes in concert with Tcf7l1, leading to the induction of lineage markers. Meanwhile, Esrrb sustains the expression of high density-specific, pluripotency-associated genes, but low seeding density differentiation reduces its occupancy on its target loci. Our demonstration of factors that transcriptionally regulate genes responsive to cell density contributes to our understanding of gene regulation in stem cells and has implications for reproducibility, as density can vary between substantially labs and experimental protocols.
Overall design
Expression and transcription factor occupancy in mouse embryonic stem cells at high and low cell seeding density.