Stem cell-specific epigenetic priming and B cell-specific transcriptional activation at the mouse Cd19 locus.
Low-level expression of multiple lineage-specific genes is a hallmark of hematopoietic stem cells (HSCs). HSCs predominantly express genes specific for the myeloid or megakaryocytic-erythroid lineages, whereas the transcription of lymphoid specific genes appears to begin after lymphoid specification. It has been demonstrated for a number of genes that epigenetic priming occurs before gene expression and lineage specification; however, little is known about how epigenetic priming of lymphoid genes is regulated. To address the question of how B cell-restricted expression is established, we studied activation of the Cd19 gene during hematopoietic development. We identified a B cell-specific upstream enhancer and showed that the developmental regulation of Cd19 expression involves precisely coordinated alterations in transcription factor binding and chromatin remodeling at Cd19 cis-regulatory elements. In multipotent progenitor cells, Cd19 chromatin is first remodeled at the upstream enhancer, and this remodeling is associated with binding of E2A. This is followed by the binding of EBF and PAX5 during B-cell differentiation. The Cd19 promoter is transcriptionally activated only after PAX5 binding. Our experiments give important mechanistic insights into how widely expressed and B lineage-specific transcription factors cooperate to mediate the developmental regulation of lymphoid genes during hematopoiesis.
Walter
Korden
K
Section of Experimental Haematology, Leeds Institute of Molecular Medicine, University of Leeds, St James's University Hospital, Leeds, United Kingdom.
Bonifer
Constanze
C
Tagoh
Hiromi
H
D000818:Animals; D018941:Antigens, CD19 / Q000235:genetics*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D018899:CpG Islands; D004247:DNA / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D004742:Enhancer Elements, Genetic; D044127:Epigenesis, Genetic; D006410:Hematopoiesis / Q000235:genetics; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D051379:Mice; D008969:Molecular Sequence Data; D051757:PAX5 Transcription Factor / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D015534:Trans-Activators / Q000378:metabolism; D015533:Transcriptional Activation
D018941:Antigens, CD19; D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA; D051757:PAX5 Transcription Factor; D015534:Trans-Activators; C489921:Ebf1 protein, mouse; C497282:Pax5 protein, mouse; C075668:Tcf3 protein, mouse