Autophagy is an intracellular process for vacuolar degradation of cytoplasmic components. The molecular machinery responsible for yeast and mammalian autophagy has begun to be elucidated at the cellular level. A genome-wide search revealed significant conservation among autophagy genes in yeast and Arabidopsis. Up till now, however, there is no report about rice autophagy associated genes. Here we cloned OsAtg8 and OsAtg4 from Oryza sativa and detected their expression patterns in various tissues. Immunoblotting analysis showed that carboxyl terminus of OsAtg8 can be cleaved in yeast cell. Mutation analysis revealed that the conserved Gly117 residue of OsAtg8 was essential for its characteristic C-terminal cleavage as similar to that found in mammalian and yeast Atg8. We further proved that OsAtg8 interacted with OsAtg4, and this interaction was not affected by the conserved Gly117 mutation. Our results demonstrate that Atg8 conjugation pathway is conserved in rice and may play important roles in rice autophagy.
自噬是內(nèi)膜包裹的細(xì)胞質(zhì)被釋放到液泡內(nèi)腔，被液泡蛋白酶降解的過程。在酵母和哺乳動物中，自噬的分子機(jī)制已經(jīng)在細(xì)胞水平被闡釋。通過全基因組的搜索，發(fā)現(xiàn)自噬基因在酵母和擬南芥中是極其保守的。直到現(xiàn)在，還沒有對水稻自噬相關(guān)基因的報道，本研究中，我們從水稻克隆了OsAtg8和OsAtg4基因，并且檢測了其在各個組織的表達(dá)模式。免疫印跡分析表明OsAt8蛋白C末端可以在酵母細(xì)胞中被切割，OsATG8蛋白中保守的Gly117的切割C末端的特性與哺乳動物的Atg8功能類似，進(jìn)一步證明OsAtg8與OsAtg4存在互作，而且互作并不受Gly117的突變的影響。結(jié)果表明，Atg8的接合通路功能在水稻中是保守的，或許在水稻自噬系統(tǒng)發(fā)揮著重要作用。