The higher structure of chromatin in the LCR of the beta-globin locus changes during development.
The beta-globin locus control region (LCR) is able to enhance the expression of all globin genes throughout the course of development. However, the chromatin structure of the LCR at the different developmental stages is not well defined. We report DNase I and micrococcal nuclease hypersensitivity, chromatin immunoprecipitation analyses for histones H2A, H2B, H3, and H4, and 3C (chromatin conformation capture) assays of the normal and mutant beta-globin loci, which demonstrate that nucleosomes at the DNase I hypersensitive sites of the LCR could be either depleted or retained depending on the stages of development. Furthermore, MNase sensitivity and 3C assays suggest that the LCR chromatin is more open in embryonic erythroblasts than in definitive erythroblasts at the primary- and secondary-structure levels; however, the LCR chromatin is packaged more tightly in embryonic erythroblasts than in definitive erythroblasts at the tertiary chromatin level. Our study provides the first evidence that the occupancy of nucleosomes at a DNase I hypersensitive site is a developmental stage-related event and that embryonic and adult cells possess distinct chromatin structures of the LCR.
Fang
Xiangdong
X
Division of Medical Genetics, Department of Medicine, Box 357720, University of Washington, Seattle, WA 98195, USA.
Yin
Wenxuan
W
Xiang
Ping
P
Han
Hemei
H
Stamatoyannopoulos
George
G
Li
Qiliang
Q
D000107:Acetylation; D000818:Animals; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism*; D003850:Deoxyribonuclease I / Q000737:chemistry; D004622:Embryo, Mammalian / Q000378:metabolism*; D047108:Embryonic Development / Q000235:genetics; D004900:Erythroblasts / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D006657:Histones / Q000378:metabolism; D006801:Humans; D019901:Locus Control Region; D051379:Mice; D008822:Mice, Transgenic; D008836:Micrococcal Nuclease / Q000737:chemistry; D009154:Mutation; D009707:Nucleosomes / Q000378:metabolism; D017433:Protein Structure, Secondary; D055544:beta-Globins / Q000235:genetics*
D002843:Chromatin; D006657:Histones; D009707:Nucleosomes; D055544:beta-Globins; D003850:Deoxyribonuclease I; D008836:Micrococcal Nuclease