Gyawali Rachana, Upadhyay Srijana, Way Joshua, Lin Xiaorong
Department of Biology, Texas A&M University, College Station, Texas, USA.
Department of Biology, Texas A&M University, College Station, Texas, USA
Appl Environ Microbiol. 2017 Feb 15;83(5). doi: 10.1128/AEM.02967-16. Print 2017 Mar 1.
, an opportunistic human fungal pathogen, can undergo a yeast-to-hypha transition in response to environmental cues. This morphological transition is associated with changes in the expression of cell surface proteins. The cell surface and secreted protein Cfl1 was the first identified adhesin in the Basidiomycota. Cfl1 has been shown to regulate morphology, biofilm formation, and intercellular communication. Four additional homologs of are harbored by the genome: , , , and The common features of this gene family are the conserved C-terminal SIGC domain and the presence of an N-terminal signal peptide. We found that all these Cfl1 homolog proteins are indeed secreted extracellularly. Interestingly, some of these secretory proteins display cell type-specific expression patterns: Cfl1 is hypha specific, Dha2 is yeast specific, and Dha1 (delayed hypersensitivity antigen 1) is expressed in all cell types but is particularly enriched at basidia. Interestingly, Dha1 is induced by copper limitation and suppressed by excessive copper in the medium. This study further attests to the physiological heterogeneity of the mating colony, which is composed of cells with heterogeneous morphotypes. The differential expression of these secretory proteins contributes to heterogeneity, which is beneficial for the fungus to adapt to changing environments. Heterogeneity in physiology and morphology is an important bet-hedging strategy for nonmobile microbes such as fungi to adapt to unpredictable environmental changes. , a ubiquitous basidiomycetous fungus, is known to switch from the yeast form to the hypha form during sexual development. However, in a mating colony, only a subset of yeast cells switch to hyphae, and only a fraction of the hyphal subpopulation will develop into fruiting bodies, where meiosis and sporulation occur. Here, we investigated a basidiomycete-specific secretory protein family. We found that some of these proteins are cell type specific, thus contributing to the heterogeneity of a mating colony. Our study also demonstrates the importance of examining the protein expression pattern at the individual-cell level in addition to population gene expression profiling for the investigation of a heterogeneous community.
作为一种机会性人类真菌病原体，可根据环境线索经历酵母到菌丝的转变。这种形态转变与细胞表面蛋白表达的变化有关。细胞表面和分泌蛋白Cfl1是担子菌中首个被鉴定的黏附素。已证明Cfl1可调节形态、生物膜形成和细胞间通讯。该基因组还包含另外四个该基因的同源物：、、和。这个基因家族的共同特征是保守的C端SIGC结构域和N端信号肽的存在。我们发现所有这些Cfl1同源蛋白确实都分泌到细胞外。有趣的是，其中一些分泌蛋白表现出细胞类型特异性的表达模式：Cfl1是菌丝特异性的，Dha2是酵母特异性的，而Dha1（迟发型超敏反应抗原1）在所有细胞类型中都有表达，但在担子处特别富集。有趣的是，Dha1受铜限制诱导，而培养基中过量的铜会抑制其表达。这项研究进一步证明了交配菌落的生理异质性，它由具有不同形态类型的细胞组成。这些分泌蛋白的差异表达导致了异质性，这有利于真菌适应不断变化的环境。生理和形态上的异质性是真菌等非移动微生物适应不可预测的环境变化的一种重要的风险规避策略。是一种普遍存在的担子菌，已知在有性发育过程中会从酵母形式转变为菌丝形式。然而，在一个交配菌落中，只有一部分酵母细胞会转变为菌丝，并且只有一小部分菌丝亚群会发育成果实体，在那里发生减数分裂和孢子形成。在这里，我们研究了一个担子菌特异性分泌蛋白家族。我们发现其中一些蛋白是细胞类型特异性的，从而导致了交配菌落的异质性。我们的研究还表明，除了群体基因表达谱分析外，在单细胞水平上检查蛋白质表达模式对于研究异质群落也很重要。
