Altered Cell Cycle Gene Expression and Apoptosis in Post-Implantation Dog Parthenotes

Abstract

Mature oocytes can be parthenogenetically activated by a variety of methods and the resulting embryos are valuable for studies of the respective roles of paternal and maternal genomes in early mammalian development. In the present study, we report the first successful development of parthenogenetic canine embryos to the post-implantation stage. Nine out of ten embryo transfer recipients became pregnant and successful in utero development of canine parthenotes was confirmed. For further evaluation of these parthenotes, their fetal development was compared with artificially inseminated controls and differentially expressed genes (DEGs) were compared using ACP RT-PCR, histological analysis and immunohistochemistry. We found formation of the limb-bud and no obvious differences in histological appearance of the canine parthenote recovered before degeneration occurred; however canine parthenotes were developmentally delayed with different cell cycle regulating-, mitochondria-related and apoptosis-related gene expression patterns compared with controls. In conclusion, our protocols were suitable for activating canine oocytes artificially and supported early fetal development. We demonstrated that the developmental abnormalities in canine parthenotes may result from defective regulation of apoptosis and aberrant gene expression patterns, and provided evidence that canine parthenotes can be a useful tool for screening and for comparative studies of imprinted genes.

Developmental and Degenerative Characterization of Porcine Parthenogenetic Fetuses during Early Pregnancy

“…In the present study, PA embryos developed with nearly normal morphologies and implanted successfully by day 26 after embryo transfer, although PA embryos were smaller than the controls. These results were consistent with those of previous studies in pigs [17] and dogs [27]. It is difficult to find any abnormalities or deformities in fetuses in gestational sacs by hormonal examination and ultrasonography.…”

“…Based on the histological analysis, there were no differences in the formation of major organs such as hearts, livers, kidneys, and brains at day 26 in PA and AI embryos. Parthenotes of other species have also shown normal embryonic and/or fetal development to day 10 in mice [28], day 21 in sheep [26], and day 30 in dogs [27]. We also evaluated the development of primitive reproductive tracts in PA embryos.…”

Species‐specific Challenges in Dog Cloning

“…Canine SCNT embryos are usually activated by exposing them to 10 μ m calcium ionophore for 4 min and then to 1.9 m m 6‐DMAP in modified synthetic oviductal fluid for 4 h (Lee et al. ; Park et al ). Although prolonged intervals between fusion and activation might promote developmental capacity of SCNT embryos in buffalo and goat (Simon et al.…”

“…Most of the activation protocols that are commonly used during canine SCNT rely on chemicals such as 6-dimethylaminopurine (6-DMAP). Canine SCNT embryos are usually activated by exposing them to 10 lM calcium ionophore for 4 min and then to 1.9 mM 6-DMAP in modified synthetic oviductal fluid for 4 h Park et al 2012). Although prolonged Oh et al (2011) intervals between fusion and activation might promote developmental capacity of SCNT embryos in buffalo and goat (Simon et al 2006;Liu et al 2011), decreasing the interval between fusion followed by chemical activation increased the cloning efficiency of dog ).…”

Somatic cell reprogrammed by oocyte: process and barricade

“…In fact, mammalian-matured oocytes own totipotent developmental potential; however, imprint genes restrict parthenogenetic embryos to develop to term. For example, mammalian parthenogenetic embryos could normally develop in the early stage; if transferred into the uteruses of recipients, they would invariably die in midgestation from imprinted gene defects and placental hypoplasia (Bischoff et al 2009;Park et al 2012). However, if imprinted genes were genetic modified to make them normally expressed, mouse parthenogenetic embryos were conferred with the ability to develop to term (Kono et al 2004).…”