Differential Gene Expression in the Uterus and Blastocyst During the Reactivation of Embryo Development in a Model of Delayed Implantation

Delayed implantation, a reversible arrest in embryo development while the embryo is at the blastocyst stage, provides an interesting window for observation of the preparation for implantation on both the embryonic and maternal sides. The American mink (Mustela vison) is a species in which delayed implantation is a normal aspect of embryo development as it consistently occurs at each breeding season. We used a transcriptome-wide approach to screen global gene expression and to identify new key genes expressed in the uterus and in the endometrium at the resumption of the embryo development, after delayed implantation. By using the suppressive subtractive hybridization (SSH) technique, two libraries of differentially expressed cDNAs, one at the uterine level and a second one at the blastocyst level, were successfully generated. Candidate genes from those two libraries were selected and their differentially expressed pattern of expression between reactivation and delayed implantation was investigated by real-time PCR and immunolocalization.