title: Genomic imprinting of IGF2, p57(KIP2) and PEG1/MEST in a marsupial, the tammar wallaby.
abstract: Genomic imprinting is widespread amongst mammals, but has not yet been found in birds. To gain a broader understanding of the origin and significance of imprinting, we have characterized three genes, from three separate imprinted clusters in eutherian mammals in the developing fetus and placenta of an Australian marsupial, the tammar wallaby Macropus eugenii. Imprinted gene orthologues of human and mouse p57(KIP2), IGF2 and PEG1/MEST genes were isolated. p57(KIP2) did not show stable monoallelic expression suggesting that it is not imprinted in marsupials. In contrast, there was paternal-specific expression of IGF2 in almost all tissues, but the biased paternal expression of IGF2 in the fetal head and placenta, demonstrates the occurrence of tissue-specific imprinting, as occurs in mice and humans. There was also paternal-biased expression of PEG1/MESTalpha. The differentially methylated region (DMR) of the human and mouse PEG1/MEST promoter is absent in the wallaby. These data confirm the existence of common imprinted regions in eutherians and marsupials during development, but suggest that the regulatory mechanisms that control imprinted gene expression differ between these two groups of mammals.
authors.affiliation: Department of Epigenetics, Medical Research Institute, Tokyo Medical and Dental University, 2-3-10 Kandasurugadai, Chiyoda-ku, Tokyo 101-0062, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Suzuki
authors.forename: Marilyn B
authors.initials: MB
authors.lastname: Renfree
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Pask
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Shaw
authors.forename: Shin
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Kohda
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kaneko-Ishino
authors.forename: Fumitoshi
authors.initials: F
authors.lastname: Ishino
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019521:Body Patterning; D050761:Cyclin-Dependent Kinase Inhibitor p57; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D005786:Gene Expression Regulation; D018507:Gene Expression Regulation, Developmental; D015723:Gene Library; D018392:Genomic Imprinting; D006257:Head / Q000196:embryology; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D007614:Macropodidae; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D010920:Placenta / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: C493964:CDKN1C protein, human; C493965:Cdkn1c protein, mouse; D050761:Cyclin-Dependent Kinase Inhibitor p57; D017931:DNA Primers; D018076:DNA, Complementary; D009687:Nuclear Proteins; D011506:Proteins; C103637:mesoderm specific transcript protein; D007335:Insulin-Like Growth Factor II