Biological differences between in vitro produced bovine embryos and parthenotes.
Parthenotes may represent an alternate ethical source of stem cells, once biological differences between parthenotes and embryos can be understood. In this study, we analyzed development, trophectoderm (TE) differentiation, apoptosis/necrosis, and ploidy in parthenotes and in vitro produced bovine embryos. Subsequently, using real-time PCR, we analyzed the expression of genes expected to underlie the observed differences at the blastocyst stage. In vitro matured oocytes were either fertilized or activated with ionomycin +6-DMAP and cultured in simple medium. Parthenotes showed enhanced blastocyst development and diploidy and reduced TE cell counts. Apoptotic and necrotic indexes did not vary, but parthenotes evidenced a higher relative proportion of apoptotic cells between inner cell mass and TE. The pluripotence-related POU5F1 and the methylation DNMT3A genes were downregulated in parthenotes. Among pregnancy recognition genes, TP-1 was upregulated in parthenotes, while PGRMC1 and PLAC8 did not change. Expression of p66(shc) and BAX/BCL2 ratio were higher, and p53 lower, in parthenotes. Among metabolism genes, SLC2A1 was downregulated, while AKR1B1, PTGS2, H6PD, and TXN were upregulated in parthenotes, and SLC2A5 did not differ. Among genes involved in compaction/blastulation, GJA1 was downregulated in parthenotes, but no differences were detected within ATP1A1 and CDH1. Within parthenotes, the expression levels of SLC2A1, TP-1, and H6PD, and possibly AKR1B1, resemble patterns described in female embryos. The pro-apoptotic profile is more pronounced in parthenotes than in embryos, which may differ in their way to channel apoptotic stimuli, through p66(shc) and p53 respectively, and in their mechanisms to control pluripotency and de novo methylation.
Gómez
Enrique
E
Genética y Reproducción Animal, SERIDA, Asturias, Spain. egomez@serida.org
Gutiérrez-Adán
Alfonso
A
Díez
Carmen
C
Bermejo-Alvarez
Pablo
P
Muñoz
Marta
M
Rodriguez
Aida
A
Otero
Jesús
J
Alvarez-Viejo
María
M
Martín
David
D
Carrocera
Susana
S
Caamaño
José Néstor
JN
D000818:Animals; D017209:Apoptosis / Q000235:genetics; D001483:Base Sequence; D001755:Blastocyst / Q000502:physiology*; D002417:Cattle; D002452:Cell Count; D017931:DNA Primers / Q000235:genetics; D047108:Embryonic Development / Q000502:physiology*; D004627:Embryonic Induction / Q000235:genetics; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D018507:Gene Expression Regulation, Developmental; D008969:Molecular Sequence Data; D009336:Necrosis; D010312:Parthenogenesis / Q000502:physiology*; D011003:Ploidies; D011247:Pregnancy; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers