Epigenetic landscaping during hESC differentiation to neural cells.
The molecular mechanisms underlying pluripotency and lineage specification from embryonic stem cells (ESCs) are still largely unclear. To address the role of chromatin structure in maintenance of pluripotency in human ESCs (hESCs) and establishment of lineage commitment, we analyzed a panel of histone modifications at promoter sequences of genes involved in maintenance of pluripotency, self-renewal, and in early stages of differentiation. To understand the changes occurring at lineage-specific gene regulatory sequences, we have established an efficient purification system that permits the examination of two distinct populations of lineage committed cells; fluorescence activated cell sorted CD133(+) CD45(-)CD34(-) neural stem cells and beta-III-tubulin(+) putative neurons. Here we report the importance of other permissive marks supporting trimethylation of Lysine 4 H3 at the active stem cell promoters as well as poised bivalent and nonbivalent lineage-specific gene promoters in hESCs. Methylation of lysine 9 H3 was found to play a role in repression of pluripotency-associated and lineage-specific genes on differentiation. Moreover, presence of newly formed bivalent domains was observed at the neural progenitor stage. However, they differ significantly from the bivalent domains observed in hESCs, with a possible role of dimethylation of lysine 9 H3 in repressing the poised genes.
Golebiewska
Anna
A
Institute of Human Genetics, University of Newcastle Upon Tyne, International Centre for Life, United Kingdom.
Atkinson
Stuart P
SP
Lako
Majlinda
M
Armstrong
Lyle
L
D002454:Cell Differentiation / Q000235:genetics*; D002460:Cell Line; D019070:Cell Lineage; D019175:DNA Methylation; D053595:Embryonic Stem Cells / Q000166:cytology*; D044127:Epigenesis, Genetic; D005434:Flow Cytometry; D015870:Gene Expression; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006657:Histones / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D009474:Neurons / Q000166:cytology*; D020411:Oligonucleotide Array Sequence Analysis; D039904:Pluripotent Stem Cells / Q000166:cytology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
D006657:Histones