RNA oxidation catalyzed by cytochrome c leads to its depurination and cross-linking, which may facilitate cytochrome c release from mitochondria.
Growing evidence indicates that RNA oxidation is correlated with a number of age-related neurodegenerative diseases, and RNA oxidation has also been shown to induce dysfunction in protein synthesis. Here we study in vitro RNA oxidation catalyzed by cytochrome c (cyt c)/H(2)O(2) or by the Fe(II)/ascorbate/H(2)O(2) system. Our results reveal that the products of RNA oxidation vary with the oxidant used. Guanosine residues are preferentially oxidized by cyt c/H(2)O(2) relative to the Fe(II)/ascorbate/H(2)O(2) system. GC/MS and LC/MS analyses demonstrated that the guanine base was not only oxidized but also depurinated to form an abasic sugar moiety. Results from gel electrophoresis and HPLC analyses show that RNA formed a cross-linked complex with cyt c in an H(2)O(2) concentration-dependent manner. Furthermore, when cyt c was associated with liposomes composed of cardiolipin/phosphatidylcholine, and incubated with RNA and H(2)O(2), it was found cross-linked with the oxidized RNA and dissociated from the liposome. Results of the quantitative analysis indicate that the release of the cyt c from the liposome is facilitated by the formation of an RNA-cyt c cross-linked complex. Thus, RNA oxidation may facilitate the release of cyt c from the mitochondrial membrane to induce apoptosis in response to oxidative stress.
Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA. mikiei.tanaka@usuhs.edu
Mikiei
M
Tanaka
Pawel
P
Jaruga
Pascal A
PA
Küpfer
Christian J
CJ
Leumann
Miral
M
Dizdaroglu
William E
WE
Sonntag
P
P
Boon Chock
D000818:Animals; D000975:Antioxidants / Q000737:chemistry; D001080:Apurinic Acid / Q000737:chemistry; D001205:Ascorbic Acid / Q000737:chemistry; D002417:Cattle; D002642:Chick Embryo; D045304:Cytochromes c / Q000737:chemistry*; D006151:Guanosine / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D006868:Hydrolysis; D008081:Liposomes / Q000737:chemistry; D024101:Mitochondrial Proteins / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D012313:RNA / Q000737:chemistry*
D000975:Antioxidants; D008081:Liposomes; D024101:Mitochondrial Proteins; D016877:Oxidants; D001080:Apurinic Acid; D006151:Guanosine; D012313:RNA; D045304:Cytochromes c; D006861:Hydrogen Peroxide; D001205:Ascorbic Acid