Fertilization and early embryology: behaviour of sperm in human oocytes displaying no or one pronucleus
after intracytoplasmic sperm injection.
Mouse zygotes with one diploid pronucleus
formed as a result of ICSI can develop normally beyond birth.
As this occurs a new nuclear envelope organizes to form the male pronucleus
. Little is known about the formation of the female pronucleus
Examination of the transparent eggs of Beroe revealed that several sperm typically penetrate the ovum (polyspermy) and that the female pronucleus
then moves around within the ovum to each of the male pronuclei in turn before fusing with one of them.
That this is, indeed, the more natural view of the case is attested by its harmony with the standard account of sexual reproduction: fertilization is completed, and development begins, not when a sperm penetrates an egg, not when the sperm head dissolves and the "male pronucleus
" forms within the egg, but only at the time of "syngamy," that is, only when the male and female pronuclei come together and their genetic materials fuse.
The hydatidiform mole is a uterine tumor that occasionally develops in which the fetus is absent and the placental tissue is abnormally large, arising most often from a sperm's fertilizing an ovum in which the female pronucleus
The egg membranes and membrane of one pronucleus
are pierced, and the gene replicas are placed inside the pronucleus
Transformation and Centrosome Inheritance
Subsequently, androgenetic mouse haploid ESCs were generated from androgenetic embryos produced by the removal of the maternal pronucleus
or by sperm injection into enucleated oocytes [39, 40].
Janssens et al., "Timing of oocyte activation, pronucleus
formation and cleavage in humans after intracytoplasmic sperm injection (ICSI) with testicular spermatozoa and after ICSI or in-vitro fertilization on sibling oocytes with ejaculated spermatozoa," Human Reproduction, vol.
Additionally, Tet 1 was detected in primordial germ cells highlighting its role in an undifferentiated profile (HAJKOVA et al., 2010), and Tet 3 is highly expressed in both oocyte and zygote, being responsible for 5-hmc increase on paternal pronucleus
, while the maternal genome is protected by binding to PGC7 protein (also known as Dppa3 or Stella) (IQBAL et al., 2011; WOSSIDLO et al., 2011).
Interestingly, the number of oocytes presenting a pronucleus
(PN) formation using sperm from boar 2012 was only four, one oocyte had 1PN and 3 oocytes had 2PN.