Polymorphism: Antifungal Drug Resistance & Adaptation in Candida

项目摘要 通常仅由一个或两个不同氨基酸组成的聚合重复序列在许多氨基酸序列中被发现。 真菌蛋白，特别是具有调节功能的蛋白。这些“polyX”区域可以是高度多态性的， 这是DNA复制过程中重复单元之间滑动的结果。待检验的一般假设 polyX多态性填补了常规突变和表观遗传学之间适应性空白。的 该R21的具体焦点是机会性酵母光滑假丝酵母（Candida glabrata），众所周知其能够开发 抗真菌唑类药物和最近的棘白菌素类药物的耐药性。而C. glabrata Pdr 1或Fks蛋白介导对这些药剂的高水平抗性，有新的证据表明， 这些突变伴随着其他遗传变化，使抗真菌药物敏感性降低， 耐受性，或补偿与Pdr 1/Fks突变相关的适应性降低。在目标1中， 将在7个唑类中评估与唑类或棘白菌素敏感性相关的36个polyX蛋白的多态性。 耐药菌株和6株棘白菌素耐药临床分离株的流行病学或遗传学相关性 匹配的敏感分离株。初步研究已经在polyQ区域确定了一个这样的多态性 转录抑制因子Tup 1A与16至32倍减少棘白菌素杀伤相关。目标2将 通过使用基因替换来构建仅在polyX上不同的菌株， 抗真菌相关蛋白的含量，然后进行敏感性和适应性测定。如果将军 假设得到支持，未来的研究将有必要评估polyX多态性在其他疾病中的作用。 真菌感染的各个方面，包括组织特异性粘附、生物膜形成和免疫逃避。

Project Abstract Polymeric repeats, typically consisting of only one or two different amino acids, are found within many fungal proteins, particularly those with regulatory functions. These “polyX” regions can be highly polymorphic, a consequence of slippage between repeat units during DNA replication. The general hypothesis to be tested here is that polyX polymorphisms fill the adaptation gap between conventional mutation and epigenetics. The specific focus of this R21 is the opportunistic yeast Candida glabrata, well known for its ability to develop resistance to antifungal azoles and, more recently, echinocandins. While single base mutations within C. glabrata Pdr1 or Fks proteins mediate high level resistance to these agents, there is emerging evidence that these mutations are accompanied by other genetic changes that confer reduced antifungal susceptibility or tolerance, or compensate for the decreased fitness associated with Pdr1/Fks mutation. In Aim 1, the polymorphism of 36 polyX proteins relevant to azole or echinocandin susceptibility will be assessed in 7 azole resistant and 6 echinocandin-resistant clinical isolates relative to their epidemiologically or phylogenetically matched susceptible isolates. Preliminary studies have identified one such polymorphism in the polyQ region of transcriptional repressor Tup1A that correlates with 16 to 32-fold reduced echinocandin killing. Aim 2 will directly test these correlations by using gene replacement to construct strains that differ only in the polyX content of an antifungal-relevant protein, followed by susceptibility and fitness assays. If the general hypothesis is supported, future studies would be warranted to evaluate the role of polyX polymorphism in other aspects of fungal infection, including tissue-specific adhesion, biofilm formation, and immune evasion.