LIS1 association with dynactin is required for nuclear motility and genomic union in the fertilized mammalian oocyte

Mutations in the human LIS1 gene cause the devastating brain disorder lissencephaly. LIS1 also regulates microtubule dynamics; it interacts with the molecular motor cytoplasmic dynein and its cofactor dynactin, and is necessary for neuronal migration. Recently, LIS1 has been suggested to mediate pronuclear migration during fertilization. Here we use rhesus monkey and bovine oocytes, as well as pronucleate-stage bovine zygotes, to determine: Lis1 RNA expression using reverse transcription-polymerase chain reaction; LIS1 protein association with dynactin using immunoprecipitation, Western blot analysis, and immunocytochemistry; and LIS1 function in mediating genomic union using antibody transfection. We find that Lis1 RNA expression increases during fertilization, that LIS1 and dynactin subunit p150/(Glued) co-immunoprecipitate and co-localize to pronuclear surfaces, and that anti-LIS1 antibodies transfected into zygotes dramatically inhibit pronuclear migration and apposition. LIS1 is, therefore, essential to mediate genomic union in a process that involves the dynein-dynactin complex. These results shed light on an additional role for LIS1 and raise implications for human reproduction.