Objective
Early (preimplantation) period of embryogenesis is the key period in mammalian development. It encompasses the onset of the developmental program and is used for embryo manipulations and improvements in livestock production. However, most mollar and cellular mechanisms which trigger and control embryonic gene expression are far to be completely understood. The aim of the present project is to study regulation of ribosomal genes (rDNA) transcription and assembly of the functional nucleolus in early mouse embryos obtained by normal fertilization, parthenogenetic activation or fusion of activated oocytes with donor cells of various origin ('reconstructed' embryos.).
It is planned to answer the next main questions: whether the transcription of rRNA genes in mouse embryos begins simultaneously with RNA pol II genes and is also regulated by the 'zygotic clock'; what is the dynamics of RNA pol I transcriptional complex assembly and rDNA-protein recognition in early mouse embryos; whether the assembly of functional nucleoli during early mouse development follows the same way as in cycling somatic cells; whether the 'nucleolar prrsor bodies (NPBs)' are associated with rDNA and rRNA; what is the dynamics of the nucleolar and nuclear transitions obtained in reconstructed mouse embryos following fusion of enucleated and activated oocytes with cells of various differentiation and proliferation capacities; what is the respective contribution of cytoplasmic and nuclear factors in the regulation of rDNA gene transcription in mouse zygotes; what is the role of protein phosphorylation/deposphorylation and chromatin structure in activating transcription of early mouse embryonic rRNA genes. It is also intended to get more insight into the environmental conditions allowing to obtain development from reconstructed embryos. To achieve these goals a wide range of cell, mollar and development techniques, such as cloning of rDNA, high resolution labeling of rDNA transcription sites with BrUTP, mapping of rDNA and rRNA with specific probes, Western blot analysis, and immunodetection of the major nucleolar proteins by confocal laser scanning and electron microscopy will be applied.
The results obtained will be published in leading international journals, used for teaching courses in Moscow, Vienna and Heidelberg Universities and French National Museum of Natural History.
Topic(s)
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69120 Heidelberg
Germany