Differential gene expression and developmental competence inin vitroproduced bovine embryos

Abstract

The embryonic developmental block occurs at the 8-cell stage in cattle and is characterized by a lengthening of the cell cycle and an increased number of embryos that stop development. The maternal-embryonic transition arises at the same stage resulting in the transcription of many genes. Gene expression studies during this stage may contribute to the understanding of the physiological mechanisms involved in the maternal-embryonic transition. Herein we identified genes differentially expressed between embryos with high or low developmental competence to reach the blastocyst stage using differential display PCR. Embryos were analysed according to developmental kinetics: fast cleavage embryos showing 8 cells at 48 h post insemination (hpi) with high potential of development (F8), and embryos with slow cleavage presenting 4 cells at 48 hpi (S4) and 8 cells at 90 hpi (S8), both with reduced rates of development to blastocyst. The fluorescence DDPCR method was applied and allowed the recovery of 176 differentially expressed bands with similar proportion between high and low development potential groups (52% to F8 and 48% in S4 and S8 groups). A total of 27 isolated fragments were cloned and sequenced, confirming the expected primer sequences and allowing the identification of 27 gene transcripts. PI3KCA and ITM2B were chosen for relative quantification of mRNA using real-time PCR and showed a kinetic and a time-related pattern of expression respectively. The observed results suggest the existence of two different embryonic genome activation mechanisms: fast-developing embryos activate genes related to embryonic development, and slow-developing embryos activate genes related to cellular survival and/or death.

Lipid characterization of in vitro-produced bovine embryos with distinct kinetics of development

“…In bovine, fast development in vitro embryo production (IVP) embryos have been found to display higher blastocyst conversion, lower developmental block and better quality regarding programmed cell death, when compared with slow development embryos, a similar phenotype to those found when antioxidants are added to the individually in vitro-cultured (IVC) cells (Garcia et al, 2015;Silva et al, 2016;Zullo et al, 2016;dos Santos et al, 2019). At the embryonic genome activation period (8-16 cells), fast development embryos also seem to activate genes related to development, whereas the slow ones activate genes related to cell survival and apoptosis (Ripamonte et al, 2012). However, how lipid metabolism occurs in embryos with different speed of development is unknown.…”

Protective effects of melatonin on the in vitro developmental competence of bovine oocytes

“…; Ripamonte et al . ). It is demonstrated that melatonin not only directly inhibits the mitochondrial permeability transition pore opening, but also prevents the release of cytochrome c from mitochondria to inhibit caspase activation and apoptosis (Asghari et al .…”

Development of bovine embryos derived from reproductive techniques

“…The exact reasons for this low efficiency are not known but have been investigated extensively in terms of genomic reprogramming. The results of these studies indicate complex changes in the patterns of epigenetic processes, especially in cloned embryos, including reduced expression of genes such as FGF4, NANOG, CASP genes and those responsible for trophoblast differentiation, and overexpression of IFNT and genes coding for angiogenetic factors, among others (Mundim et al 2009;Campos et al 2010;Rodríguez-Alvarez et al 2010;Leidenfrost et al 2011;Ripamonte et al 2011;Gong et al 2012).…”