Max-von-Pettenkofer-Institute, Ludwig-Maximilians-University, Munich, Germany.
Int J Med Microbiol. 2013 Mar;303(2):90-7. doi: 10.1016/j.ijmm.2012.11.005. Epub 2013 Jan 14.
In filamentous fungi, the septal pore controls the exchange between neighbouring hyphal compartments. Woronin bodies are fungal-specific organelles that plug the pore in case of physical damage. The Hex protein is their major and essential component. Hex proteins of different size are predicted in the data base for pathogenic and non-pathogenic Aspergillus species. However, using specific monoclonal antibodies, we identified 2 dominant HexA protein species of 20 and 25kDa in A. fumigatus, A. terreus, A. nidulans, and A. oryzae. HexA and Woronin bodies were found in A. fumigatus hyphae, but also in resting conidia. Using monoclonal antibodies, a GFP-HexA fusion protein, and an RFP protein fused to the putative peroxisomal targeting sequence of HexA, we analyzed the spatial localization and dynamics of Woronin bodies in A. fumigatus as well as their formation from peroxisomes. In intact hyphae, some Woronin bodies were found in close proximity to the septal pore, while the majority was distributed in the cytoplasm. Septum-associated Woronin bodies show a minimal lateral movement, while the cytosolic Woronin bodies are highly dynamic. The distribution of Woronin bodies and their co-localization pattern with peroxisomes revealed no evidence that Woronin bodies arise predominantly at the apical tip of A. fumigatus hyphae. We found that Woronin bodies are able to plug septal pores of A. fumigatus in case of damage. Woronin bodies therefore contribute to the stress resistance and potentially also to the virulence of A. fumigatus, which renders them a potential target for future anti-fungal strategies.
在丝状真菌中，隔膜孔控制着相邻菌丝隔室之间的物质交换。Woronin 体是真菌特有的细胞器，在发生物理损伤时会堵塞孔道。Hex 蛋白是其主要且必需的组成部分。在致病性和非致病性 Aspergillus 物种的数据库中预测到不同大小的 Hex 蛋白。然而，使用特异性单克隆抗体，我们在 A. fumigatus、A. terreus、A. nidulans 和 A. oryzae 中鉴定出 20kDa 和 25kDa 两种主要的 HexA 蛋白。HexA 和 Woronin 体在 A. fumigatus 菌丝中被发现，也存在于静止孢子中。使用单克隆抗体、GFP-HexA 融合蛋白和与 HexA 假定过氧化物酶体靶向序列融合的 RFP 蛋白，我们分析了 Woronin 体在 A. fumigatus 中的空间定位和动态及其从过氧化物酶体形成的过程。在完整的菌丝中，一些 Woronin 体被发现靠近隔膜孔，而大多数分布在细胞质中。与隔膜相关的 Woronin 体的侧向运动最小，而细胞质中的 Woronin 体具有高度的动态性。Woronin 体的分布及其与过氧化物酶体的共定位模式表明，Woronin 体主要不是在 A. fumigatus 菌丝的顶端形成的。我们发现 Woronin 体能够在 A. fumigatus 发生损伤时堵塞隔膜孔。因此，Woronin 体有助于提高 A. fumigatus 的抗应激能力，并且可能也有助于其毒力，这使它们成为未来抗真菌策略的潜在目标。
