含DnaJ样锌指结构域的蛋白质参与质体功能和发育的不同方面。最近报道这些蛋白质中的一些在细胞核和质体中具有双重亚细胞定位。这个家庭的一个成员,PSA2(AT2G34860),被发现位于类囊体管腔并调节光系统I(PSI)的组装。然而,PSA2也被注释为胚囊发育停滞3(EDA3),因为观察到其胚囊发育停滞在两核阶段。在这项研究中,我们鉴定了eda3突变体,并证明了,与野生型(WT)植物相比,突变体有较短的角果,每株植物的角果更少,每个角果的种子更少。在突变体的长角果中观察到流产和未发育的胚珠。通过免疫印迹分析,我们发现,与成熟叶片中的叶绿体定位不同,EDA3定位于种子的核中。从EDA3的推导的氨基酸序列中鉴定出核定位信号,并且还证明足以将其融合肽引导到细胞核中。
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 eda3 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.