ABSTRCT The human genome encodes approximately 60 Fe2+, 2-oxoglutarate (2-OG)-dependent oxygenases. Some members of this family of proteins have been recently demonstrated to assume important roles in the oxidative conversion and demethylation of 5-methyl-2?-deoxycytidine in DNA as well as N6-methyladenosine (m6A), N1- methyladenosine (m1A), and 5-methylcytidine (m5C) in RNA. No systematic studies, however, have yet been conducted for assessing the roles of the entire family of Fe2+, 2-OG-dependent oxygenases and flavin adenine dinucleotide (FAD)-dependent histone demethylases LSD1 and LSD2 in the oxidative conversion and demethylation of RNA. In addition, the ?-amino group of some proteins are known to be methylated, and this ?- N-methylation is conserved from Escherichia coli to man. Although the enzymes involved in the deposition of this post-translational modification is known, no enzyme has been discovered to function in the removal of methyl group from the ?-amino group of proteins. Here we propose to employ a combination of genetic, biochemical and bioanalytical approaches to investigate comprehensively the roles of Fe2+, 2-OG-dependent oxygenases and LSD1/LSD2 in the oxidative conversion and demethylation of RNA and ?-N-demethylation of proteins. We will also assess how the functions of some DNA repair proteins are modulated by the enzymes involved in protein ?-N-demethylation. The outcome of the proposed research will lead to significant insights into the dynamic regulations of RNA methylation and protein ?-N-methylation. The proposed research may also provide new knowledge about how environmental exposure elicits adverse human health consequences by perturbing the regulatory mechanisms of RNA methylation and protein ?-N-methylation.
The emphasis of this grant application is placed on understanding the novel functions of a family of dioxygenases in RNA and protein demethylation. The outcome of the proposed research may provide a better understanding of how genetic deficiency and environmental exposure confer adverse human health effects.
