Genetic variation in oocyte phenotype revealed through parthenogenesis and cloning: correlation with differences in pronuclear epigenetic modification.
Previous studies revealed that oocytes of different genetic strains (e.g, C57BL/6 and DBA/2) modify maternal and paternal pronuclei differently, affecting early preimplantation development. To determine whether these strain-dependent effects would also apply to oocyte modifications of somatic cell nuclei introduced during cloning procedures, we compared the efficiency of development of parthenogenetic and cloned embryos made with DBA/2, C57BL/6, and (B6D2)F1 oocytes. Our results reveal significant differences in the ability of oocytes of different genetic backgrounds to support parthenogenetic development in different culture media. Additionally, our results reveal oocyte strain-dependent differences in the ability to support cloned embryo development beyond what can be accounted for on the basis of differences in parthenogenesis. Thus, the previously documented differences in oocyte-directed parental genome modification are accompanied in the same strains by differences in the ability of oocytes to modify somatic cell nuclei and support clonal development, raising the possibility that these oocyte functions may be mediated by related mechanisms. These results provide a genetic basis for further studies seeking to identify specific genes that determine oocyte phenotype, as well as genes that determine the success of nuclear reprogramming and clonal development.
Gao
Shaorong
S
The Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.
Czirr
Eva
E
Chung
Young Gie
YG
Han
Zhiming
Z
Latham
Keith E
KE
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D019976:Cloning, Organism; D005314:Embryonic and Fetal Development; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D009865:Oocytes / Q000502:physiology*; D010312:Parthenogenesis; D010641:Phenotype; D014019:Tissue Donors
D002352:Carrier Proteins