Abstract
Cells degrade various kinds of cellular components by autophagy under nutrient starvation conditions. However, little is known about how much autophagy contributes to the degradation of each cellular component and whether such degradation is selective or not. In this study, we have examined the change in rRNA contents in tobacco BY-2 cells cultured under sucrose starvation conditions, because we suppose that ribosomes can be good nutrients for starved cells. rRNA was degraded upon sucrose deprivation, and the net degradation was inhibited by the autophagy inhibiter 3-methyladenine by approximately 50%. On the other hand, our morphological observation suggests that 3-methyladenine inhibits autophagy almost completely under the same condition. These results show that the autophagic pathway contributes to the degradation of rRNA and suggest that other pathways exist for the degradation of rRNA. In the presentation, we will report our data, and discuss possible degradation pathways of rRNA.
