Analysis of microtubule-organizing centers (MTOCs) in Aspergillus nidulans and Neurospora crassa

真核细胞中微管的形成依赖于大的、多亚单位的蛋白质复合体，称为微管组织中心(MTOCs)。在酿酒酵母中，MTOC被嵌入到核膜中，被命名为纺锤体-极体(SPB)，这是一个研究非常深入的例子。在裂殖酵母中，三种不同的MTOCs在细胞周期的不同阶段产生MT阵列，多个间期iMTOCs位于核膜SPBS和赤道eMTOCs的胞质分裂中。这三个因素在空间和时间上都是有规律的。在发现了γ-微管蛋白的丝状真菌nidulans中，描述了两种稳定的MTOCs，即SPBS和间隔MTOCs(SMTOCs)。我们发现，sMTOCs通过无序蛋白Spa10锚定在隔膜上，其蛋白质组成类似于SPBS的外斑。在粗糙脉孢菌中，SPBS聚合了有丝分裂和细胞质中的MTs，但在细胞质的生长顶端也有MTOCs存在的证据。对其生化成分和活性一无所知。在这里，我们建议进行一项比较研究的MTOCs在一个nidulans和n.crassa。将研究几种蛋白质的作用，如莫扎特1(MztA和MTZ-1)或含有J结构域的蛋白质RSPA。除了MTOCs的生化组成外，组装的层次结构将被拆解。此外，将采用非目标方法，如BioID或GFP-Trap技术，以发现新的结构和监管组件。

Microtubule formation in eukaryotic cells depends on large, multi-subunit protein complexes, called Microtubule-organizing centres (MTOCs). One extremely well-studied MTOC is the one in Saccharomyces cerevisiae, where the MTOC is embedded into the nuclear envelope and named spindle-pole body (SPB). In Schizosaccharomyces pombe three different MTOCs generate the MT arrays during different stages of the cell cycle, multiple interphase iMTOCs located in the nuclear envelope, the SPBs, and equatorial, eMTOCs, during cyokinesis. All three are spatially and temporally regulated. In the filamentous fungus Aspergillus nidulans, in which gamma-tubulin was discovered, two stable MTOCs were described, the SPBs and septal MTOCs (sMTOCs). We found that sMTOCs are anchored at septa through the disordered protein Spa10, and that the protein composition resembles the one of the outer plaque of SPBs. In Neurospora crassa SPBs polymerize mitotic and cytoplasmic MTs, but in addition there is evidence for MTOCs in the growing tip in the cytoplasm. Nothing is known about the biochemical composition and the activity. Here, we propose to perform a comparative study of the MTOCs in A. nidulans and N. crassa. The role of several proteins, such as MOZART 1 (MztA and MTZ-1) or the J-domain containing protein RspA, will be studied. Besides the biochemical composition of MTOCs, the hierarchy of the assembly will be unraveled. In addition, non-targeted approaches, such as BioID or GFP-trap technology, will be undertaken to discover novel structural and regulatory components.