State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China.
Int J Mol Sci. 2020 Oct 27;21(21):7979. doi: 10.3390/ijms21217979.
The DnaJ-like zinc finger domain-containing proteins are involved in different aspects of plastid function and development. Some of these proteins were recently reported to have dual subcellular localization in the nucleus and plastids. One member of this family, PSA2 (AT2G34860), was found to localize to the thylakoid lumen and regulate the assembly of photosystem I (PSI). However, PSA2 was also annotated as Embryo sac Development Arrest 3 (EDA3) from the observation that its embryo sac development was arrested at the two-nuclear stage. In this study, we characterized the mutant, and demonstrated that, as compared with the wild-type (WT) plants, the mutant has shorter siliques, fewer siliques per plant, and fewer seeds per silique. Both aborted and undeveloped ovules were observed in siliques of the mutant. By immunoblot analysis, we found that, different from the chloroplast localization in mature leaves, EDA3 localizes in the nucleus in seeds. A nuclear localization signal was identified from the deduced amino acid sequence of EDA3, and also proved to be sufficient for directing its fusion peptide into the nucleus.
DnaJ 样锌指蛋白参与质体功能和发育的多个方面。这些蛋白中的一些最近被报道具有核和质体的双重亚细胞定位。该家族的一个成员 PSA2（AT2G34860）被发现定位于类囊体腔，并调节光系统 I（PSI）的组装。然而，由于观察到其胚囊发育在双核期被阻止，PSA2 也被注释为胚囊发育停滞 3（EDA3）。在这项研究中，我们对 突变体进行了表征，并证明与野生型（WT）植物相比，突变体的果荚更短，每株植物的果荚更少，每个果荚的种子也更少。在突变体的果荚中观察到了败育和未发育的胚珠。通过免疫印迹分析，我们发现，与成熟叶片中的质体定位不同，EDA3 在种子中定位于核内。从 EDA3 的推导氨基酸序列中鉴定出一个核定位信号，并且还被证明足以将其融合肽引导到核内。
