Oda Ken, Bignell Elaine, Kang S Earl, Momany Michelle
Fungal Biology Group and Department of Plant Biology, University of Georgia, Athens, Georgia, USA 30602.
Current address: National Research Institute of Brewing (NRIB), Hiroshima, Japan 739-0046.
Med Mycol. 2017 Jun 1;55(4):445-452. doi: 10.1093/mmy/myw085.
Aspergillus fumigatus is the most common airborne pathogen causing fatal mycoses in immunocompromised patients. During the first 8 hours of development A. fumigatus conidia break dormancy, expand isotopically, establish an axis of polarity, and begin to extend germ tubes in a polar manner. The transition from isotropic to polar growth is critical for tissue invasion and pathogenesis. In the current work, we used two-color microarrays to examine the A. fumigatus transcriptome during early development, focusing on the isotropic to polar switch. The most highly regulated transcripts in the isotropic to polar switch did not include known polarity genes. Transcripts encoding the Cdc42 module, polarisome components, and septins, known to be critical players in polarity, showed relatively steady levels during the isotropic to polar switch. Indeed, these transcripts were present in dormant conidia, and their levels changed little from dormancy through germ tube emergence. Not only did the isotropic to polar switch show little change in the expression of key polarity genes of the Cdc42 module, polarisome, and septins, it also showed the lowest overall levels of both up- and downregulation in early development.
烟曲霉是免疫功能低下患者中导致致命真菌病的最常见空气传播病原体。在发育的最初8小时内，烟曲霉分生孢子打破休眠，进行等径膨胀，建立极性轴，并开始以极性方式延伸芽管。从等径生长到极性生长的转变对于组织侵袭和发病机制至关重要。在当前的研究中，我们使用双色微阵列来检测烟曲霉早期发育过程中的转录组，重点关注从等径生长到极性生长的转变。在从等径生长到极性生长的转变过程中，调控最为显著的转录本并不包括已知的极性基因。编码Cdc42模块、极化体成分和隔膜蛋白的转录本，这些已知在极性形成中起关键作用的蛋白，在从等径生长到极性生长的转变过程中表现出相对稳定的水平。事实上，这些转录本在休眠分生孢子中就已存在，从休眠到芽管出现，它们的水平变化不大。从等径生长到极性生长的转变不仅在Cdc42模块、极化体和隔膜蛋白的关键极性基因表达上变化很小，而且在早期发育中上调和下调的总体水平也是最低的。
