Mouse embryos with paternal duplication of an imprinted chromosome 7 region die at midgestation and lack placental spongiotrophoblast

K. John McLaughlin, Piroska Szabó, Hélène Haegel, Jeffrey R. Mann

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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 possess excess Igf2 RNA as might be expected from the parental-specific activities of these genes in normal embryos.

Original languageEnglish
Pages (from-to)265-270
Number of pages6
Issue number1
Publication statusPublished - 1 Jan 1996
Externally publishedYes


  • Chromosome 7
  • Genetics
  • Imprinting
  • Mouse
  • Translocation
  • Uniparental duplication

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