ABSTRACT
Objective: This research intends to unravel the temporal expression profiles of genes involved in three developmentally important signaling pathways [transforming growth factor-beta [TGF-beta], fibroblast growth factor [FGF] and wingless/int [WNT]] during pre- and peri-implantation goat embryo development
Materials and Methods: In this experimental study, we examined the transcripts that encoded the ligand, receptor, intracellular signal transducer and modifier, and the downstream effector, for each signaling pathway. In vitro mature MII oocytes and embryos at three distinctive stages [8-16 cell stage, day-7 [D7] blastocysts and day-14 [D14] blastocysts] were separately prepared in triplicate for comparative real-time reverse transcriptase polymerase chain reaction [RT-PCR] using the selected gene sets
Results: Most components of the three signaling pathways were present at more or less stable levels throughout the assessed oocyte and embryo developmental stages. The transcripts for TGF-beta, FGF and WNT signaling pathways were all induced in unfertilized MII-oocytes. However, developing embryos showed gradual patterns of decrease in the activities of TGF-beta, FGF and WNT components with renewal thereafter
Conclusion: The results suggested that TGF-beta, FGF and WNT are maternally active signaling pathways required during earlier, rather than later, stages of pre- and peri-implantation goat embryo development
ABSTRACT
Background: Little is understood about the regulation of gene expression during early goat embryo development. This study investigated the expression profile of 19 genes, known to be critical for early embryo development in mouse and human, at five different stages of goat in vitro embryo development [oocyte, 8-16 cell, morula, day-7 blastocyst, and day 14 blastocyst]
Materials and Methods: In this experimental study, stage-specific profiling using real time-quantitative polymerase chain reaction [RT-qPCR] revealed robust and dynamic patterns of stage-specific gene activity that fall into four major clusters depending on their respective mRNA profiles
Results: The gradual pattern of reduction in the maternally stored transcripts without renewal thereafter [cluster-1: Lifr1, Bmpr1, Alk4, Id3, Ctnnb, Akt, Oct4, Rex1, Erk1, Smad1 and 5] implies that their protein products are essential during early cleavages when the goat embryo is silent and reliant to the maternal legacy of mRNA. The potential importance of transcription augment at day-3 [cluster-2: Fzd, c-Myc, Cdc25a, Sox2] or day-14 [cluster-3: Fgfr4, Nanog] suggests that they are nascent embryonic mRNAs which intimately involved in the overriding of MET or regulation of blastocyst formation, respectively. The observation of two expression peaks at both day-3 and day-14 [cluster-4: Gata4, Cdx2] would imply their potential importance during these two critical stages of pre-and peri-implantation development
Conclusion: Evolutionary comparison revealed that the selected subset of genes has been rewired in goat and human/goat similarity is greater than the mouse/goat or bovine/goat similarities. The developed profiles provide a resource for comprehensive understanding of goat preimplantation development and pluripotent stem cell engineering as well