MBD2 is a critical component of a methyl cytosine-binding protein complex isolated from primary erythroid cells.
The chicken embryonic beta-type globin gene, rho, is a member of a small group of vertebrate genes whose developmentally regulated expression is mediated by DNA methylation. Previously, we have shown that a methyl cytosine-binding complex binds to the methylated rho-globin gene in vitro. We have now chromatographically purified and characterized this complex from adult chicken primary erythroid cells. Four components of the MeCP1 transcriptional repression complex were identified: MBD2, RBAP48, HDAC2, and MTA1. These 4 proteins, as well as the zinc-finger protein p66 and the chromatin remodeling factor Mi2, were found to coelute by gel-filtration analysis and pull-down assays. We conclude that these 6 proteins are components of the MeCPC. In adult erythrocytes, significant enrichment for MBD2 is seen at the inactive rho-globin gene by chromatin immunoprecipitation assay, whereas no enrichment is observed at the active beta(A)-globin gene, demonstrating MBD2 binds to the methylated and transcriptionally silent rho-globin gene in vivo. Knock-down of MBD2 resulted in up-regulation of a methylated rho-gene construct in mouse erythroleukemic (MEL)-rho cells. These results represent the first purification of a MeCP1-like complex from a primary cell source and provide support for a role for MBD2 in developmental gene regulation.
Kransdorf
Evan P
EP
Department of Internal Medicine, Massey Cancer Center, Virginia Commonwealth University, 401 College Street, PO Box 980037, Richmond, VA 23298-0037, USA.
Wang
Shou Zhen
SZ
Zhu
Sheng Zu
SZ
Langston
Timothy B
TB
Rupon
Jeremy W
JW
Ginder
Gordon D
GD
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D045744:Cell Line, Tumor; D002642:Chick Embryo; D002645:Chickens; D018899:CpG Islands; D004247:DNA / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D041905:Erythroid Cells / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D005914:Globins / Q000235:genetics; D004915:Leukemia, Erythroblastic, Acute / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D034622:RNA Interference; D015854:Up-Regulation
D004268:DNA-Binding Proteins; C115368:MBD2 protein; D046912:Multiprotein Complexes; D005914:Globins; D004247:DNA