title: The absence of a DNA replication checkpoint in porcine zygotes.
abstract: It has been demonstrated that in the zygotes of some mammals a unique checkpoint controls the onset of DNA replication. Thus, DNA replication begins in the maternal pronucleus only after the paternal pronucleus is fully formed. In our experiments we have investigated whether this checkpoint also operates in porcine zygotes produced either by in vitro fertilization (IVF) or by intracytoplasmic sperm injection (ICSI). Our results show that the onset of DNA replication occurs in the maternal pronucleus even in the presence of an intact sperm head in zygotes produced by ICSI, as well as in polyspermic eggs where some sperm heads are intact or male pronuclei are not yet fully developed. We conclude that in porcine zygotes there is an absence of the DNA replication checkpoint that is typical for some other mammals.
authors.affiliation: Institute of Animal Production, POB 1, CS-104 01 Prague 114, Czech Republic. vackova.irena@vuzv.cz
authors.forename: Irena
authors.initials: I
authors.lastname: Vackova
authors.forename: Radomir
authors.initials: R
authors.lastname: Kren
authors.forename: Pasqualino
authors.initials: P
authors.lastname: Loi
authors.forename: Vladimír
authors.initials: V
authors.lastname: Krylov
authors.forename: Josef
authors.initials: J
authors.lastname: Fulka
mesh_terms: D000818:Animals; D004261:DNA Replication / Q000502:physiology; D005260:Female; D008297:Male; D008954:Models, Biological; D013045:Species Specificity; D020554:Sperm Injections, Intracytoplasmic; D013084:Sperm-Ovum Interactions / Q000502:physiology; D013552:Swine / Q000235:genetics* / Q000502:physiology; D015053:Zygote / Q000378:metabolism*