Importin α7 Is Essential for Zygotic Genome Activation and Early Mouse Development

Importin alpha is involved in the nuclear import of proteins. It also contributes to spindle assembly and nuclear membrane formation, however, the underlying mechanisms are poorly understood. Here, we studied the function of importin alpha 7 by gene targeting in mice and show that it is essential for early embryonic development. Embryos lacking importin alpha 7 display a reduced ability for the first cleavage and arrest completely at the two-cell stage. We show that the zygotic genome activation is severely disturbed in these embryos. Our findings indicate that importin alpha 7 is a new member of the small group of maternal effect genes.