The maternal nucleolus is essential for early embryonic development in mammals.
With fertilization, the paternal and maternal contributions to the zygote are not equal. The oocyte and spermatozoon are equipped with complementary arsenals of cellular structures and molecules necessary for the creation of a developmentally competent embryo. We show that the nucleolus is exclusively of maternal origin. The maternal nucleolus is not necessary for oocyte maturation; however, it is necessary for the formation of pronuclear nucleoli after fertilization or parthenogenetic activation and is essential for further embryonic development. In addition, the nucleolus in the embryo produced by somatic cell nuclear transfer originates from the oocyte, demonstrating that the maternal nucleolus supports successful embryonic development.
Ogushi
Sugako
S
Graduate School of Science and Technology, Kobe University, Kobe 657-8501, Japan. ogushi@cdb.riken.jp
Palmieri
Chiara
C
Fulka
Helena
H
Saitou
Mitinori
M
Miyano
Takashi
T
Fulka
Josef
J
D000818:Animals; D002466:Cell Nucleolus / Q000502:physiology*; D065150:Cellular Reprogramming; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000502:physiology* / Q000648:ultrastructure; D047108:Embryonic Development; D053595:Embryonic Stem Cells / Q000502:physiology / Q000648:ultrastructure; D005260:Female; D005307:Fertilization in Vitro; D051379:Mice; D008813:Mice, Inbred ICR; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000502:physiology* / Q000648:ultrastructure; D010312:Parthenogenesis; D020554:Sperm Injections, Intracytoplasmic; D013552:Swine; D015053:Zygote / Q000502:physiology / Q000648:ultrastructure