Pronucleus


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Related to Pronucleus: Female pronucleus

pronucleus

[prō′nü·klē·əs]
(cell and molecular biology)
One of the two nuclear bodies of a newly fertilized ovum, the male pronucleus and the female pronucleus, the fusion of which results in the formation of the germinal (cleavage) nucleus.

Pronucleus

 

the haploid nucleus of a sex cell, or gamete. During fertilization, the diploid nucleus of the zygote, or synkaryon, is formed by the fusion of two pronuclei; the chromosome sets of both pronuclei are joined in the synkaryon.

In multicellular organisms and a number of protozoans that are anisogamous, there are female and male pronuclei. The female pronucleus is the nucleus of a mature egg cell, or macro-gamete. The male pronucleus is formed by the swelling of the nucleus of a spermatozoid, or microgamete, after it has become embedded in the cytoplasm of an egg cell. In isogamous unicellular organisms, the fusing pronuclei, like the gametes themselves, are morphologically indistinguishable. During autogamy, pronuclei that have been formed in the same cell fuse; they are usually sister nuclei. During conjugation in infusorians, two pronuclei form in each partner—a stationary pronucleus and a migrating pronucleus. There is first an exchange of migrating pronuclei between partners through a cytoplasmic bridge, which is followed by the fusion of the pronuclei in each of the partners.

References in periodicals archive ?
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 is absent.
The egg membranes and membrane of one pronucleus are pierced, and the gene replicas are placed inside the pronucleus.
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.