ES cell pluripotency and germ-layer formation require the SWI/SNF chromatin remodeling component BAF250a.
ATP-dependent chromatin remodeling complexes are a notable group of epigenetic modifiers that use the energy of ATP hydrolysis to change the structure of chromatin, thereby altering its accessibility to nuclear factors. BAF250a (ARID1a) is a unique and defining subunit of the BAF chromatin remodeling complex with the potential to facilitate chromosome alterations critical during development. Our studies show that ablation of BAF250a in early mouse embryos results in developmental arrest (about embryonic day 6.5) and absence of the mesodermal layer, indicating its critical role in early germ-layer formation. Moreover, BAF250a deficiency compromises ES cell pluripotency, severely inhibits self-renewal, and promotes differentiation into primitive endoderm-like cells under normal feeder-free culture conditions. Interestingly, this phenotype can be partially rescued by the presence of embryonic fibroblast cells. DNA microarray, immunostaining, and RNA analyses revealed that BAF250a-mediated chromatin remodeling contributes to the proper expression of numerous genes involved in ES cell self-renewal, including Sox2, Utf1, and Oct4. Furthermore, the pluripotency defects in BAF250a mutant ES cells appear to be cell lineage-specific. For example, embryoid body-based analyses demonstrated that BAF250a-ablated stem cells are defective in differentiating into fully functional mesoderm-derived cardiomyocytes and adipocytes but are capable of differentiating into ectoderm-derived neurons. Our results suggest that BAF250a is a key component of the gene regulatory machinery in ES cells controlling self-renewal, differentiation, and cell lineage decisions.
Gao
Xiaolin
X
Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Richard Simches Research Center, 185 Cambridge Street, Boston, MA 02114, USA.
Tate
Peri
P
Hu
Ping
P
Tjian
Robert
R
Skarnes
William C
WC
Wang
Zhong
Z
D017667:Adipocytes / Q000166:cytology; D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D019070:Cell Lineage; D049109:Cell Proliferation; D042002:Chromatin Assembly and Disassembly / Q000235:genetics*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D047108:Embryonic Development; D053595:Embryonic Stem Cells / Q000166:cytology*; D005260:Female; D050437:Genes, Developmental; D005855:Germ Layers / Q000166:cytology / Q000196:embryology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000166:cytology; D032383:Myocytes, Cardiac / Q000166:cytology; D009687:Nuclear Proteins / Q000378:metabolism*; D039904:Pluripotent Stem Cells / Q000166:cytology*; D014157:Transcription Factors / Q000378:metabolism*
C511511:Arid1a protein, mouse; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C445179:SWI-SNF-B chromatin-remodeling complex; D014157:Transcription Factors