The Effect of the NADPH Oxidase YNO1 on Translational Fidelity

The hypothesized relationship between translational fidelity and ageing is complex, dating back half a century and so far represented by few known conclusions. Translational fidelity is known to remain constant with ageing, but the mechanism through which this is possible is currently a mystery. Recently, the yeast NADPH oxidase Yno1p was implicated in the regulation of translational fidelity, and the relationship between Yno1p and translational fidelity was investigated here in more detail. Through luciferase-based translational fidelity assays, here was shown that YNO1 expression is negatively correlated with high frequency of stop-codon read-through, and this pattern is mimicked by overnight ROS exposure, providing evidence that ROS produced by Yno1p improves translational fidelity. Furthermore, YCK1, YCK2 and HEK2 was shown to be independently essential in mediating the fidelity improvement signal from Yno1p to the translational machinery. Additionally, the mechanism by which hydrogen peroxide exposure and Yno1p improves fidelity appears to be independent, but both can produce additive improvements in fidelity. Using growth assays, overexpression of YNO1 and hydrogen peroxide exposure were both shown to increase sensitivity to nourseothricin (NTC), a translational error- inducing drug. YNO1 was found to be an important regulator of translational fidelity.