Two mechanisms drive pronuclear migration in mouse zygotes

Nat Commun. 2021 Feb 5;12(1):841. doi: 10.1038/s41467-021-21020-x.

Abstract

A new life begins with the unification of the maternal and paternal chromosomes upon fertilization. The parental chromosomes first become enclosed in two separate pronuclei near the surface of the fertilized egg. The mechanisms that then move the pronuclei inwards for their unification are only poorly understood in mammals. Here, we report two mechanisms that act in concert to unite the parental genomes in fertilized mouse eggs. The male pronucleus assembles within the fertilization cone and is rapidly moved inwards by the flattening cone. Rab11a recruits the actin nucleation factors Spire and Formin-2 into the fertilization cone, where they locally nucleate actin and further accelerate the pronucleus inwards. In parallel, a dynamic network of microtubules assembles that slowly moves the male and female pronuclei towards the cell centre in a dynein-dependent manner. Both mechanisms are partially redundant and act in concert to unite the parental pronuclei in the zygote's centre.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / genetics
  • Actins / metabolism
  • Animals
  • Cell Nucleus / metabolism*
  • Cell Nucleus / ultrastructure
  • Female
  • Fertilization / genetics*
  • Formins / genetics*
  • Formins / metabolism
  • Gene Expression Regulation, Developmental
  • Genes, Reporter
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred CBA
  • Microfilament Proteins / genetics*
  • Microfilament Proteins / metabolism
  • Microtubules / metabolism
  • Microtubules / ultrastructure
  • Movement
  • Nerve Tissue Proteins / genetics*
  • Nerve Tissue Proteins / metabolism
  • Oocytes / metabolism
  • Oocytes / ultrastructure
  • Spermatozoa / metabolism
  • Spermatozoa / ultrastructure
  • Zygote / metabolism*
  • Zygote / ultrastructure
  • rab GTP-Binding Proteins / genetics*
  • rab GTP-Binding Proteins / metabolism

Substances

  • Actins
  • Formins
  • Luminescent Proteins
  • Microfilament Proteins
  • Nerve Tissue Proteins
  • Spire1 protein, mouse
  • formin 2 protein, mouse
  • red fluorescent protein
  • Green Fluorescent Proteins
  • rab11 protein
  • rab GTP-Binding Proteins