The Fe(II and 2OG dependent dioxygenase Jmjd6 in Hydra: Highly conserved in all animals, essential in vertebrates - does it have an evolutionary conserved function

点击翻译按钮获取中文摘要

The JmjC-domain family of Fe(II) and 2-oxoglutarate dependent dioxygenases contains about 60 members in humans. They are involved in hydroxylating substrates such as proteins or nucleic acids; and in reversing arginine or lysine N-methylations dividing them in hydroxylases and demethylases. As their activity depends on oxygen tension and tricarboxylic acid intermediates they are able to link protein and nucleic acid modifications with environmental conditions and this is important for some dynamic epigenetic modifications. Jmjd6 is a member of this family with great biological importance for vertebrate embryonic development and oncogenic mechanisms. Despite the fact that Jmjd6 is essential for mouse and zebrafish development the molecular function of human Jmjd6 is insufficiently understood and in parts controversially discussed. In early metazoans there is almost no information about the biochemical and physiological roles of Jmjd6. The remarkably strong sequence conservation of Jmjd6 from Hydra to humans indicates that there is a conserved function that has to be uncovered. We therefore suggest to characterize Jmjd6 in the early metazoan Hydra, which is an ideal model organism to combine biochemical with developmental studies. Using mouse monoclonal antibodies against Hydra-Jmjd6 we will identify proteins and protein domains that interact with Hydra-Jmjd6 and compare those with the human Jmjd6 interactome. We will carry out X-ray structural analysis to understand the evolution of the 3-D-structure of Jmjd6 and define its enzymatic activity towards the identified substrates. In addition, we are planning to study the effects of hypoxia and nutrition on mRNA- and protein levels as well as on the subnuclear distribution of Jmjd6, and we will analyze the role of Jmjd6 for Hydra developmental processes such as regeneration and budding. Characterization of transgenic lines and application of pan-specific Fe(II)- and 2OG dependent dioxygenase inhibitors, Jmjd6 specific inhibitors and siRNAs will be employed. A second knockdown approach generating Jmjd6 knockdown Hydra-lines using the vector pHyVec12 will complement this. We expect that these investigations will shed light on the molecular and biological roles of Jmjd6 in humans.