Regulation of placental development

Peri-attachment factor, ovine placental lactogen, and ovine growth hormone are three proteins expressed in developing conceptus and placenta. Bovine peri-attachment factor (bPF) was originally detected in bovine conceptus and adult kidney. We have detected ovine, equine and porcine homologs of bPF expressed in conceptus and adult tissues. The timing of PF expression in conceptus of these species coincides with that reported for bPF. The predicted PF protein contains a nuclear targeting sequence that we have verified as functional. By immunoblot we detected PF fusion protein within the nucleus of two eukaryotic cell lines, where it is believed that PF may act as a transcriptional co-activator or co-repressor.; Several in vitro studies have investigated the transcriptional regulation of ovine placental lactogen (oPL); however, there has been no in vivo analysis of the transcriptional regulation of oPL. Deletions of the oPL promoter were fused to EGFP to make a reporter construct for use in transgenic nuclear cloning. While successful in generating pregnancies, nuclear cloning could not produce tangible results with the promoter-reporter constructs. We then focused on viral infection of placental tissue. Enriched fractions of BNCs could be successfully infected with both an adenovirus and lentivirus that carried GFP coding sequence regulated by the CMV promoter. Viral infection represents a route which could be used to elucidate the transcriptional regulation of oPL.; Ovine growth hormone (oGH) expression has been reported in the placenta. We used in situ hybridization to localize the expression of oGH to uterine epithelium. We next investigated the role of placental oGH by administering exogenous GH during the normal expression window of placental oGH. Maternal GH administration did not impact placental or fetal growth or the expression of oGH, oPL, IGF-I, and IGF-II in placental tissues. Within the caruncle, IGF binding protein-1 (IGF BP-1) was decreased, IGF BP-3 and -4 were increased, and IGF BP-2 was unchanged by treatment. In the cotyledon, IGF BP-1 and -4 were increased, IGF BP-2 decreased, and IGF BP-3 was unchanged by maternal GH treatment. While not altering placental or fetal growth, exogenous GH does change IGF BP expression, which has important roles in placental development.