title: Mouse embryos with paternal duplication of an imprinted chromosome 7 region die at midgestation and lack placental spongiotrophoblast.
abstract: Imprinted genomic regions have been defined by the production of mice with uniparental inheritance or duplication of homologous chromosome regions. With most of the genome investigated, paternal duplication of only distal chromosomes 7 and 12 results in the lack of offspring, and prenatal lethality is presumed. Aberrant expression of imprinted genes in these two autosomal regions is therefore strongly implicated in the periimplantation lethality of androgenetic embryos. We report that mouse embryos with paternal duplication of distal chromosome 7 (PatDup.d7) die at midgestation and lack placental spongiotrophoblast. Thus, the much earlier death of androgenones must involve paternal duplication of other autosomal regions, acting independently of or synergistically with PatDup.d7. The phenotype observed is similar, if not identical to, that resulting from mutation of the imprinted distal chromosome 7 gene, Mash2, which in normal midgestation embryos exhibits spongiotrophoblast-specific maternally active/paternally inactive (m+/p-) allelic expression. Thus, the simplest explanation for the PatDup.d7 phenotype is p-/p- expression of this gene. We also confirm that PatDup.d7 embryos lack H19 RNA and posses excess Igf2 RNA as might be expected from the parental-specific activities of these genes in normal embryos.
authors.affiliation: Division of Biology, Beckman Research Institute of the City of Hope, Duarte, California 91010, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: McLaughlin
authors.forename: P
authors.initials: P
authors.lastname: Szabó
authors.forename: H
authors.initials: H
authors.lastname: Haegel
authors.forename: J R
authors.initials: JR
authors.lastname: Mann
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000235:genetics; D001483:Base Sequence; D002869:Chromosome Aberrations; D017931:DNA Primers / Q000235:genetics; D005314:Embryonic and Fetal Development / Q000235:genetics*; D005260:Female; D005313:Fetal Death / Q000235:genetics*; D018392:Genomic Imprinting; D007335:Insulin-Like Growth Factor II / Q000235:genetics; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000235:genetics; D010920:Placenta / Q000002:abnormalities*; D011247:Pregnancy; D012313:RNA / Q000235:genetics / Q000378:metabolism; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D017411:Ribonucleoproteins, Small Nuclear; D014327:Trophoblasts / Q000473:pathology; D055517:snRNP Core Proteins
chemical_list: D001324:Autoantigens; D017931:DNA Primers; C094335:H19 long non-coding RNA; D009124:Muscle Proteins; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D017411:Ribonucleoproteins, Small Nuclear; D055517:snRNP Core Proteins; D012313:RNA; D007335:Insulin-Like Growth Factor II