Role of Estrogen Receptor α in Mouse Oviduct Gene Expression

Estrogen receptor α (ERα) is a nuclear transcription factor crucial for the female reproductive function. We previously reported that mice lacking epithelial ERα in the epithelial cells of female reproductive tract (Wnt7aCre+;Esr1fl/fl, conditional knockout or cKO) were infertile, in part, due to an implantation defect. To determine if oviductal dysfunction also contributed to their infertility, we examined the fertilization rates and embryo development in vivo during the first few days of pregnancy. At 0.5 days post coitum (dpc), cKO females had significantly fewer zygotes than wild type control littermates (WT). At 1.5 dpc, cKO females had no 2-cell embryos at all; only dead oocytes or embryos and empty zona pellucidas were observed. These results indicate that lack of ERα in the oviductal epithelium resulted in alterations in the oviductal microenvironment that were detrimental to the embryos. Microarray analysis revealed dramatic differences in gene expression between cKO and WT oviducts collected at 0.5 dpc and significant but less dramatic differences at 1.5 dpc. These findings indicate that signaling via epithelial ERα is essential to generate an oviductal milieu supportive of fertilization and embryo development.and may have implications for infertility in women. The oviduct samples were collected from female reproductive tract epithelial ER α knockout (cKO) and wild type control littermates (WT) at days 1 and 2 of pregnancy (0.5 and 1.5 days post coitum). Each experimental group contains 4 replicates. Gene expression analysis was conducted by using Agilent Whole Mouse Genome 4×44 multiplex format oligo arrays (no. 014868; Agilent Technologies, Santa Clara, CA)