MITOCHONDRIA TRANSFER INTO MOUSE OVA BY MICROINJECTION

A method for mitochondria isolation and interspecific transfer of mito chondria was developed in mice. Mitochondria were isolated from Mus sp retus liver samples for microinjection into fertilized ova obtained fr om superovulated M. musculus domesticus females. Electron microscopic observations of mitochondria preparations used for microinjection demo nstrated intact mitochondrial vesicles with little microsomal contamin ation. Species-specific nested PCR primers complementary to sequence d ifferences in the mitochondrial DNA D-loop region revealed high rates of successful transfer of foreign mitochondria after isolation and inj ection into zygotes cultured through the blastocyst stage of embryonic development. Of 217 zygotes, 67 survived mitochondria injection and 2 3 out of 37 zygotes developed were at the blastocyst-stage of embryoni c development after 4.5 days of in vitro culture. All 23 of these blas tocysts contained detectable levels of foreign mitochondria. These res ults represent an initial step in developing a model system to study m itochondrial dynamics and development of therapeutic strategies for hu man metabolic diseases affected by aberrations in mitochondrial functi on or mutation.