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Di Ding, Mabel Enriquez-Algeciras, Kunjan R. Dave, Miguel Perez-Pinzon, Sanjoy Bhattacharya; Deimination Modulates Atp5b Mrna Transport In Retinal Ganglion Cells. Invest. Ophthalmol. Vis. Sci. 2012;53(14):780.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the role of deimination in mitochondrial surface protein synthesis in a transgenic mouse model (ND4 mice) of multiple sclerosis, which accompanies visual defects.
Animals were used adhering to ARVO statement for utilization of animals in vision research.RNA export factor protein (REF) deimination status was evaluated in both wild type and ND4 mice by Western blot analysis and mass spectrometry. Retinal and/or purified mitochondrial lysates from mice (n=3) were subjected to immunoprecipitation (IP) using anti-REF antibody. Total mRNA from IP product of mitochondrial and retinal cytosolic extract was isolated followed by real-time PCR to evaluate the ATP5b/REF binding specificity. Elctrophoretic Mobility Shift Assays (EMSAs) were performed to compare the binding strength of non-deiminated and deiminated REF for ATP5b. The respiratory control index was determined to evaluate the respiratory efficiency. All experiments were repeated three times and results were shown as mean ± SD.
Deimination refers to the post translational modification of protein-bound arginine into citrulline catalyzed by peptidylarginine deiminases (PADs). REF exhibits significant loss of deimination in ND4 mice compared to wild type. We found ATP5b mRNA transport is associated with REF. REF transport to mitochondria in ND4 mice is decreased as a result of loss of REF deimination. As a consequence, ND4 mice showed respiratory chain defect. EMSA result indicated that the binding strength to ATP5b mRNA of non-deiminated REF is significantly less than the deiminated REF. We demonstrated that inhibition of deimination in primary Retinal ganglion cells and PC 12 cell line reduced the mitochondrial ATP synthase activity compared to the control.
We conclude that the impaired deimination of REF leads to defect in mitochondrial mRNA transport, which is likely to be a critical factor in mitochondrial dysfunction in ND4 mice.
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