The interaction between nucleus and cytoplasm can be explored throughnuclear transfer. We describe here another tool to investigate thisinteraction: MII meiotic apparatus transfer (MAT) between mouse oocytes. Inthis study, the MII oocyte meiotic apparatus or spindle from C57BL/6 mice, ablack strain, was transferred into an enucleated metaphase oocyte fromKunming mouse, a white strain. The results showed that the enucleation rateby treating oocytes with 3% sucrose was 100%, but the electrofusionefficiency was very low, with only 17.6% of reconstructed karyoplast-recipientcytoplasm pairs fused. When the fused oocytes were exposed to spermatozoafrom C57BL/6 mice, 9 of 11 (82%) were fertilised. Eight reconstructedembryos at 1- to 4-cell stages were transferred into the oviducts of twosynchronously pregnant Kunming strain fosters and one delivered two normalC57BL/6 offspring. This study indicates that MII meiotic apparatus orspindle sustains normal structure and function after micromanipulationand electrofusion. MAT provides a model for further research on theapplication of this technique to assisted human reproduction.