During oocyte growth, maturation and zygote development, chromatin
structure undergoes continuous changes to regulate different nuclear
activities. Condensin plays an essential role in chromatin
configuration. Here, through oocyte-specific conditional knockout of
SMC2, a core component of the condensin complex, we showed that SMC2 is
essential for the production of healthy eggs and early embryo
development. Maternal SMC2 knockout caused chromosome condensation
defects in oocytes, and subsequently inhibited proper pronuclear
organization in zygotes. As a result, pronuclear function was impaired
and DNA damage was accumulated, which prevented the development of
embryos beyond the zygote stage.