a Department of Plant Pathology and Microbiology , Texas A&M University , 2132 TAMU , College Station , Texas 77845.
b Center for Biomolecular Science and Engineering , Naval Research laboratory , Washington , District of Columbia 20375.
Mycologia. 2019 Jan-Feb;111(1):13-25. doi: 10.1080/00275514.2018.1543927. Epub 2019 Jan 30.
The maintenance of cell shape requires finely tuned and robust vesicle trafficking in order to provide sufficient plasma membrane materials. The hyphal cells of filamentous fungi are an extreme example of cell shape maintenance due to their ability to grow rapidly and respond to the environment while keeping a relatively consistent shape. We have previously shown that two phospholipid flippases, which regulate the asymmetry of specific phospholipids within the plasma membrane, are important for hyphal growth in Aspergillus nidulans. Here, we examine the rest of the phospholipid flippases encoded by A. nidulans by obtaining single and double deletions of all four family members, dnfA, dnfB, dnfC, and dnfD. We find that deleting dnfC does not impart a noticeable phenotype, by itself or with other deletions, but that dnfD, the homolog of the essential yeast gene neo1, is important for conidiation. dnfD deletion mutants form misshapen conidiophore vesicles that are defective in metulae formation. We localize DnfD to late Golgi equivalents, where it appears just before dissociation of this organelle. We propose that DnfD functions in a trafficking process that is specifically required for the morphological changes that take place during conidiation.
细胞形状的维持需要精细调节和稳健的囊泡运输，以便为质膜提供足够的材料。丝状真菌的菌丝细胞是细胞形状维持的一个极端例子，因为它们能够在保持相对一致的形状的同时快速生长并对环境做出反应。我们之前已经表明，两种磷脂翻转酶（调节质膜中特定磷脂的不对称性）对于构巢曲霉中的菌丝生长很重要。在这里，我们通过获得所有四个家族成员（dnfA、dnfB、dnfC 和 dnfD）的单基因和双基因缺失，来研究构巢曲霉中其余的磷脂翻转酶。我们发现，dnfC 的缺失本身或与其他缺失一起，并没有赋予明显的表型，但 dnfD（酵母必需基因 neo1 的同源物）对分生孢子形成很重要。dnfD 缺失突变体形成畸形的分生孢子囊泡，在小梗形成中存在缺陷。我们将 DnfD 定位到晚期高尔基体等效物，在那里它出现在该细胞器分离之前。我们提出，DnfD 在一个特定的运输过程中发挥作用，该过程对于分生孢子形成过程中发生的形态变化是必需的。
