The role of diSUMO-like DSUL and targets for female gametogenesis and early embryogenesis in maize

小泛素相关修饰因子（SUMO）对许多蛋白质的可逆翻译后修饰在调节广泛的基本细胞和发育过程中起着重要作用。例如，遗传学研究表明，sumo酰化对动物和植物的早期胚胎发生至关重要。虽然SUMO靶蛋白主要与单体SUMO结合，但也有多SUMO酰化现象发生。在草中，我们现在已经确定了第一个蛋白质DSUL，天然由两个首尾相接的sumo样蛋白结构域组成，类似于哺乳动物的作用和diumo样DSUL FAT10和ISG15的靶标，包含两个泛素样（UbL）结构域。DSUL的表达仅限于雌性配子体和合子的微孔区。功能研究表明，DSUL在玉米雌性配子体发生过程中对细胞核定位、细胞规格和生存能力都是必需的。我们现在将研究(i) DSUL是否使用SUMO酶机制进行偶联和解偶联，还是使用自己的机制进行DSULylation和deDSULylation，确定（ii）玉米中的DSUL底物，作为研究DSUL修饰蛋白质调节细胞和发育过程的机制的先决条件。DSUL靶蛋白应（iii）与玉米中的SUMO和Ub靶蛋白进行比较。最后，我们将（iv）阐明DSUL在不对称受精卵分裂和纺锤体组织中的生物学作用。

Reversible post-translational modifications of numerous proteins by small ubiquitinrelated modifiers (SUMO) play a major role in regulating a broad array of basic cellular and developmental processes. Genetic studies have shown, for example, that SUMOylation is essential for early embryogenesis in animals and plants. While SUMO target proteins are predominantly conjugated to monomeric SUMO, polySUMOylation has also been shown to occur. In grasses we have now identified the first protein, DSUL, naturally consisting of two head-to-tail SUMO-like protein domains, similar to mammalian Role and targets of diSUMO-like DSUL FAT10 and ISG15 that contain two ubiquitin-like (UbL) domains. Expression of DSUL is restricted to the micropylar region of the female gametophyte and zygote. Functional studies indicated that DSUL is required for nuclei positioning, cell specification and viability during female gametogenesis in maize. We will now study whether (i) DSUL uses the SUMO enzymatic machinery for conjugation and deconjugation or an own machinery for DSULylation and deDSULylation, identify (ii) DSUL substrates in maize as a prerequisite to study the mechanisms through which DSUL modification of proteins regulates cellular and developmental processes. DSUL target proteins shall (iii) be compared to SUMO und Ub targets in maize. Finally, we will (iv) elucidate the biological role of DSUL for asymmetric zygote division and spindle organization.