Preferentially localized dynein and perinuclear dynactin associate with nuclear pore complex proteins to mediate genomic union during mammalian fertilization.
Fertilization is complete once the parental genomes unite, and requires the migration of the egg nucleus to the sperm nucleus (female and male pronuclei, respectively) on microtubules within the inseminated egg. Neither the molecular mechanism of pronucleus binding to microtubules nor the role of motor proteins in regulating pronuclear motility has been fully characterized, and the failure of zygotic development in some patients suggests that they contribute to human infertility. Based on the minus-end direction of female pronuclear migration, we propose a role for cytoplasmic dynein and dynactin in associating with the pronuclear envelope and mediating genomic union. Our results show that dynein intermediate and heavy chains preferentially concentrate around the female pronucleus, whereas dynactin subunits p150Glued, p50 and p62 localize to the surfaces of both pronuclei. Transfection of antibodies against dynein and dynactin block female pronuclear migration in zygotes. Both parthenogenetic activation in oocytes and microtubule depolymerization in zygotes significantly reduce the localization of dynein to the female pronucleus but do not inhibit the pronuclear association of dynactin. When immunoprecipitated from zygotes, p150Glued associates with nuclear pore complex proteins, as well as the intermediate filament vimentin and dynein. Antibodies against nucleoporins and vimentin inhibit pronuclear apposition when transfected into zygotes. We conclude that preferentially localized dynein and perinuclear dynactin associate with the nuclear pore complex and vimentin and are required to mediate genomic union. These data suggest a model in which dynein accumulates and binds to the female pronucleus on sperm aster microtubules, where it interacts with dynactin, nucleoporins and vimentin.
Program in Molecular and Cellular Biosciences, Department of Cell and Developmental Biology, Oregon Health and Science University, Portland, OR 97201, USA.
Christopher
C
Payne
Vanesa
V
Rawe
João
J
Ramalho-Santos
Calvin
C
Simerly
Gerald
G
Schatten
D000818:Animals; D002417:Cattle / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism; D000072159:Dynactin Complex; D004398:Dyneins / Q000378:metabolism*; D005260:Female; D005306:Fertilization / Q000235:genetics*; D023281:Genomics; D008253:Macaca mulatta / Q000502:physiology; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D008958:Models, Molecular; D028861:Nuclear Pore Complex Proteins / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism; D021122:Protein Subunits / Q000378:metabolism*; D013094:Spermatozoa / Q000378:metabolism; D015053:Zygote / Q000378:metabolism
D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; D028861:Nuclear Pore Complex Proteins; D021122:Protein Subunits; D004398:Dyneins