title: Transcriptome asymmetry within mouse zygotes but not between early embryonic sister blastomeres.
abstract: Transcriptome regionalization is an essential polarity determinant among metazoans, directing embryonic axis formation during normal development. Although conservation of this principle in mammals is assumed, recent evidence is conflicting and it is not known whether transcriptome asymmetries exist within unfertilized mammalian eggs or between the respective cleavage products of early embryonic divisions. We here address this by comparing transcriptome profiles of paired single cells and sub-cellular structures obtained microsurgically from mouse oocytes and totipotent embryos. Paired microsurgical spindle and remnant samples from unfertilized metaphase II oocytes possessed distinguishable profiles. Fertilization produces a totipotent 1-cell embryo (zygote) and associated spindle-enriched second polar body whose paired profiles also differed, reflecting spindle transcript enrichment. However, there was no programmed transcriptome asymmetry between sister cells within 2- or 3-cell embryos. Accordingly, there is transcriptome asymmetry within mouse oocytes, but not between the sister blastomeres of early embryos. This work places constraints on pre-patterning in mammals and provides documentation correlating potency changes and transcriptome partitioning at the single-cell level.
authors.affiliation: Laboratory of Mammalian Molecular Embryology, RIKEN Center for Developmental Biology, Kobe, Japan.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: VerMilyea
authors.forename: Matthias
authors.initials: M
authors.lastname: Maneck
authors.forename: Naoko
authors.initials: N
authors.lastname: Yoshida
authors.forename: Isabell
authors.initials: I
authors.lastname: Blochberger
authors.forename: Emi
authors.initials: E
authors.lastname: Suzuki
authors.forename: Toru
authors.initials: T
authors.lastname: Suzuki
authors.forename: Rainer
authors.initials: R
authors.lastname: Spang
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Klein
authors.forename: Anthony C F
authors.initials: AC
authors.lastname: Perry
mesh_terms: D000818:Animals; D001757:Blastomeres / Q000378:metabolism*; D019521:Body Patterning / Q000502:physiology*; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D051379:Mice; D046228:Microarray Analysis; D016133:Polymerase Chain Reaction; D015053:Zygote / Q000378:metabolism*
chemical_list: D017931:DNA Primers