An Arabidopsis homolog of yeast ATG6/VPS30 is essential for pollen germination
An Arabidopsis homolog of yeast ATG6/VPS30 is essential for pollen germination
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DOI：
10.1104/pp.106.093864
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发表时间：
2007-03-01
期刊：
影响因子：
7.4
通讯作者：
Ohsumi, Yoshinori
中科院分区：
文献类型：
--
作者：
Fujiki, Yuki;Yoshimoto, Kohki;Ohsumi, Yoshinori
酵母（Saccharomyces cerevisiae）Atg 6/Vps 30是自噬和液泡水解酶（如羧肽酶Y）分选所必需的。然而，在高等真核生物中，ATG 6/VPS 30同源物在囊泡分选中的作用仍然不清楚。在这里，我们表明，AtATG 6，拟南芥（拟南芥）同源的酵母ATG 6/VPS 30，恢复自噬和空泡分选的羧肽酶Y在酵母atg 6/vps 30突变体。在拟南芥细胞中，绿色荧光蛋白AtAtg 6蛋白定位于点状结构，并与前自噬体结构的标记蛋白AtAtg 8共定位。通过T-DNA插入破坏AtATG 6导致雄性不育，这通过正反交实验证实。AtATG 6杂合植物（AtATG 6/atatg 6）与四联体突变体杂交的显微镜分析显示，AtATG 6缺陷的花粉发育正常，但不发芽。由于其他atatg突变体是可育的，AtAtg 6可能介导花粉萌发的方式独立的自噬。我们认为拟南芥Atg 6/Vps 30不仅在自噬中起作用，而且在花粉萌发中也起着关键作用。
Yeast (Saccharomyces cerevisiae) Atg6/Vps30 is required for autophagy and the sorting of vacuolar hydrolases, such as carboxypeptidase Y. In higher eukaryotes, however, roles for ATG6/VPS30 homologs in vesicle sorting have remained obscure. Here, we show that AtATG6, an Arabidopsis (Arabidopsis thaliana) homolog of yeast ATG6/VPS30, restored both autophagy and vacuolar sorting of carboxypeptidase Y in a yeast atg6/vps30 mutant. In Arabidopsis cells, green fluorescent protein-AtAtg6 protein localized to punctate structures and colocalized with AtAtg8, a marker protein of the preautophagosomal structure. Disruption of AtATG6 by T-DNA insertion resulted in male sterility that was confirmed by reciprocal crossing experiments. Microscopic analyses of AtATG6 heterozygous plants (AtATG6/atatg6) crossed with the quartet mutant revealed that AtATG6-deficient pollen developed normally, but did not germinate. Because other atatg mutants are fertile, AtAtg6 likely mediates pollen germination in a manner independent of autophagy. We propose that Arabidopsis Atg6/Vps30 functions not only in autophagy, but also plays a pivotal role in pollen germination.