TY - JOUR
T1 - Complex developmental patterns of histone modifications associated with the human β-globin switch in primary cells
AU - Hsu, Mei
AU - Richardson, Christine A.
AU - Olivier, Emmanuel
AU - Qiu, Caihong
AU - Bouhassira, Eric E.
AU - Lowrey, Christopher H.
AU - Fiering, Steven
N1 - Funding Information:
We would like to thank Rodwell Mabaera for technical assistance and Ann Dean for advice on antibodies and critical reading of the manuscript. We wish to acknowledge the University of Washington Birth Defects Laboratory for providing fetal liver samples. Primary funding was provided by National Institutes of Health (NIH) grants HL73431 (S.F.) and HL73442 (C.L.). Additional funding was provided by NIH grants T32 AI07363, GM075037 (E.E.B.) and HL088467 (E.E.B.) and by the Knights of the York Cross of Honour (C.L.). No financial interest/relationships with financial interest relating to the topic of this article have been declared.
PY - 2009/7
Y1 - 2009/7
N2 - Objective: The regulation of the β-globin switch remains undetermined, and understanding this mechanism has important benefits for clinical and basic science. Histone modifications regulate gene expression and this study determines the presence of three important histone modifications across the β-globin locus in erythroblasts with different β-like globin-expression profiles. Understanding the chromatin associated with weak γ gene expression in bone marrow cells is an important objective, with the goal of ultimately inducing postnatal expression of weak γ-globin to cure β-hemoglobinopathies. Materials and Methods: These studies use uncultured primary fetal and bone marrow erythroblasts and human embryonic stem cell-derived primitive-like erythroblasts. Chromatin immunoprecipitation with antibodies against modified histones reveals DNA associated with such histones. Precipitated DNA is quantitated by real-time polymerase chain reaction for 40 sites across the locus. Results: Distribution of histone modifications differs at each developmental stage. The most highly expressed genes at each stage are embedded within large domains of modifications associated with expression (acetylated histone H3 [H3ac] and dimethyl lysine 4 of histone H3 [H3K4me2]). Moderately expressed genes have H3ac and H3K4me2 in the immediate area around the gene. Dimethyl lysine 9 of histone H3 (H3K9me2), a mark associated with gene suppression, is present at the ε{lunate} and γ genes in bone marrow cells, suggesting active suppression of these genes. Conclusion: This study reveals complex patterns of histone modifications associated with highly expressed, moderately expressed, and unexpressed genes. Activation of γ postnatally will likely require extensive modification of the histones in a large domain around the γ genes.
AB - Objective: The regulation of the β-globin switch remains undetermined, and understanding this mechanism has important benefits for clinical and basic science. Histone modifications regulate gene expression and this study determines the presence of three important histone modifications across the β-globin locus in erythroblasts with different β-like globin-expression profiles. Understanding the chromatin associated with weak γ gene expression in bone marrow cells is an important objective, with the goal of ultimately inducing postnatal expression of weak γ-globin to cure β-hemoglobinopathies. Materials and Methods: These studies use uncultured primary fetal and bone marrow erythroblasts and human embryonic stem cell-derived primitive-like erythroblasts. Chromatin immunoprecipitation with antibodies against modified histones reveals DNA associated with such histones. Precipitated DNA is quantitated by real-time polymerase chain reaction for 40 sites across the locus. Results: Distribution of histone modifications differs at each developmental stage. The most highly expressed genes at each stage are embedded within large domains of modifications associated with expression (acetylated histone H3 [H3ac] and dimethyl lysine 4 of histone H3 [H3K4me2]). Moderately expressed genes have H3ac and H3K4me2 in the immediate area around the gene. Dimethyl lysine 9 of histone H3 (H3K9me2), a mark associated with gene suppression, is present at the ε{lunate} and γ genes in bone marrow cells, suggesting active suppression of these genes. Conclusion: This study reveals complex patterns of histone modifications associated with highly expressed, moderately expressed, and unexpressed genes. Activation of γ postnatally will likely require extensive modification of the histones in a large domain around the γ genes.
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U2 - 10.1016/j.exphem.2009.04.006
DO - 10.1016/j.exphem.2009.04.006
M3 - Article
C2 - 19460472
AN - SCOPUS:67049086913
SN - 0301-472X
VL - 37
SP - 799-806.e4
JO - Experimental Hematology
JF - Experimental Hematology
IS - 7
ER -