Control of gene expression during embryo-maternal communication

To identify molecular mechanisms which govern embryo-maternal communication, this dissertation examined the regulatory phenomena associated with uniquely expressed uterine and embryo genes in the pig.; The porcine IGF-I gene was cloned, and regions of this gene exhibited enhancer like activities in the uterus of early pregnant pigs. Up-regulation of IGF-I transcription by ER-alpha was observed in uterine cells. Analysis of the 5'-ends of IGF-I gene transcripts in pig endometrium and ovarian granulosa cells revealed tissue-specific initiator elements. Gel retardation assays for nuclear proteins which bound to the related sequence element in the IGF-I gene promoter also were performed. Lastly, two alternatively spliced novel exons were identified within IGF-I transcripts in porcine ovarian granulosa cells. These new findings may explain the hormonal, temporal, and tissue-specific aspects of IGF-I gene expression in the uterus and ovary.; Other components of the IGF system were examined relative to their embryomaternal gene expression patterns and transcriptional regulation. The porcine acid labile subunit gene was cloned, sequenced and its expression observed. Transient transfections of porcine IGFBP-2 gene constructs into primary cultures of pig endometrial cells identified a functional enhancer element within the upstream region. Two TCAGGG and E-box motifs and an 33-mer sequence (direct repeat of 15 nucleotides with a three base pair spacing) were confirmed to be functional cis-elements of the endometrial IGFBP-2 gene. Collectively, these results identified new DNA binding motifs and cognate binding proteins implicated in endometrial IGFBP-2 transcriptional regulation. The last set of studies comprised a pilot expressed sequence tag analysis to identify the gene transcripts in pig embryos at peri-implantation. Twenty clones were analyzed, and six further characterized for mRNA expression levels. The results demonstrated the temporal and cell-type-specific expression of the corresponding mRNAs in embryos and endometrium.; The collective results illustrate the significant utility of the application of molecular biology to understanding and unraveling the processes of embryo-maternal communication with relevance to both human and animal reproduction.