Expression Patterns of Cell Adhesion Molecules in Bovine Preimplantation Embryos Cultured in vitro

This study aimed to investigate gene expression patterns throughout preimplantation embryos and their comparative expression in morphological quality blastocysts using real-time RT-PCR. Bovine oocytes underwent maturation process, fertilized and were cultured in vitro. Degree of fragmentation and differentiation were the criteria to categorize day-7 blastocysts as of good and poor quality. All of the embryos from each developmental stage were used to quantify transcript abundance. It was found that E-cadherin was highly expressed in immature and mature oocytes, then it decreased at 2- to 16-cell stages, and later increased in morula and blastocyst stages. The β-catenin transcript was highly abundant up to the 4-cell stage and further down regulated in the later stages. However, the transcript abundance of desmocollin 2 (DSC2) was high only at morula and blastocyst stages. The relative abundance of E-cadherin, β-catenin and DSC2 mRNA in good quality blastocysts were statistically significantly higher than in poor quality blastocysts. Moreover, only the protein expression levels of E-cadherin and β-catenin were significantly higher in good than in poor blastocysts. In conclusion, E-cadherin and β-catenin are highly expressed in good qualit