Fig 1.
Experimental design employed in this study.
Two days after synchronized oestrus, in vitro-produced embryos were transferred in pools of 50 Day-2 (IVF = Day 0) 2- to 4-cell stage embryos into the oviduct ipsilateral to the corpus luteum of postpartum dairy cows that were either milked (i.e. lactating) post-calving (LACT) or were dried off immediately at calving (i.e. nonlactating; DRY) via transvaginal endoscopic transfer. On Day 4, the oviducts were flushed and 16-cell stage embryos were snap-frozen in pools of 5 on an individual cow basis before mRNA extraction for RNAseq. A control group was maintained under in vitro culture (IVC) and processed in the same way for RNA Seq. Pools of five Day-2 embryos (n = 5) were also subjected to mRNA extraction for RNAseq.
Table 1.
Embryo recovery from postpartum nonlactating (DRY) or lactating (LACT) cows on Day 4 following oestrus.
Fig 2.
Differentially expressed genes (DEG) between Day-2 and Day-4 embryos undergoing embryonic genome activation in three environmental conditions.
The identified DEG were organized into five groups according to the condition that was driving the gene expression. Additionally, DEG in each group could be separated into clusters according to the direction of the gene expression. The boxplots represent the average expression for genes in each cluster for each condition. IVC: in vitro culture; DRY: nonlactating dairy cows, LACT: lactating dairy cows.
Fig 3.
Differentially expressed genes (DEG) in Day-4 embryos undergoing embryonic genome activation in three environmental conditions.
The identified DEG were classified into six clusters according to the direction of the gene expression. The boxplots represent the average expression for genes in each cluster for each condition. IVC: in vitro culture; DRY: nonlactating dairy cows, LACT: lactating dairy cows.
Fig 4.
Expression levels for genes involved in selected enriched ontological terms by the differentially expressed genes.
Gene expression was measured in Day-2 embryos or Day-4 embryos undergoing embryonic genome activation (EGA) in one of three conditions (IVC, DRY, or LACT). IVC: in vitro culture; DRY: nonlactating dairy cows, LACT: lactating dairy cows.
Fig 5.
Network representation for differentially expressed genes enriching ontological terms involved in energy regulation.
The nodes are coloured according to the expression levels on Day-2 embryos or Day-4 embryos undergoing embryonic genome activation (EGA) in one of three conditions (IVC, DRY, or LACT). IVC: in vitro culture; DRY: nonlactating dairy cows, LACT: lactating dairy cows.
Table 2.
Differentially expressed genes among embryos that underwent embryonic gene activation in different conditions enriching for ontological terms involved in energy regulation.