title: Dynamic changes in the localization of five members of the methyl binding domain (MBD) gene family during murine and bovine preimplantation embryo development.
abstract: There are five methyl binding domain (MBD) proteins characterized by a methyl CpG-binding domain. Four MBD proteins (MeCP2 and MBDs 1-3) are linked to transcriptional repression and one (MBD4), to DNA repair. During preimplantation development, the embryo undergoes global demethylation following fertilization and selective remethylation following the maternal to zygotic transition (MZT). This study characterized changes in MBD mRNA expression and protein localization during both murine and bovine preimplantation development. These species were selected because they undergo MZT at different developmental stages. Gene expression profiling during preimplantation development detected the presence of all MBDs examined, although stage and species-specific differences were observed. MBD2 was not expressed in murine or bovine oocytes and MeCP2 was not detected in murine blastocysts, subcellular protein localization was found to vary at time points critical in development. Most MBDs showed species-specificity in localization patterns and differences were found between individual MBDs. MBD1 localization is consistent with a novel role during MZT for both species. MBD3, known to play a crucial role in murine embryogenesis, was highly localized to the nucleus before and after, but not during the MZT in the bovine. MBD2, MBD4, and MeCP2 show varying patterns of localization which indicate possible roles in the early cleavage stages and in inner cell mass differentiation. Further experiments are currently underway to define discreet functional roles for specific MBDs during bovine preimplantation embryogenesis.
authors.affiliation: Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia. nancy.dcruz@med.monash.edu.au
authors.forename: Nancy T
authors.initials: NT
authors.lastname: Ruddock-D'Cruz
authors.forename: Jun
authors.initials: J
authors.lastname: Xue
authors.forename: Katrina J
authors.initials: KJ
authors.lastname: Wilson
authors.forename: Corey
authors.initials: C
authors.lastname: Heffernan
authors.forename: Sivachelvi
authors.initials: S
authors.lastname: Prashadkumar
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Cooney
authors.forename: L Gabriel
authors.initials: LG
authors.lastname: Sanchez-Partida
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: French
authors.forename: Michael K
authors.initials: MK
authors.lastname: Holland
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000737:chemistry* / Q000378:metabolism*; D002417:Cattle / Q000196:embryology* / Q000235:genetics; D018899:CpG Islands; D004268:DNA-Binding Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D047108:Embryonic Development / Q000235:genetics*; D004706:Endodeoxyribonucleases / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D051783:Methyl-CpG-Binding Protein 2 / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D012333:RNA, Messenger / Q000378:metabolism; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; C115368:MBD2 protein; C489323:Mbd1 protein, mouse; C492013:Mbd3 protein, mouse; D051783:Methyl-CpG-Binding Protein 2; D012333:RNA, Messenger; D014157:Transcription Factors; D004706:Endodeoxyribonucleases; C492249:Mbd4 protein, mouse