Genetic Characterization of phosphomannan biosynthesis in C. auris

耳念珠菌是近年来出现的一种真菌性致病菌。这种新出现的物种在全世界范围内崛起， 自日本首次发现以来的过去十年中，这种微生物已成为一个公共卫生问题， 其抗真菌耐药性和在重症监护和疗养院设施中持续存在的能力。的原因之一 这种持续存在的能力背后是许多临床分离株显示出多药耐药性，在罕见的情况下， 可以是抗泛的。最近，我们研究了八个C。auris分离并发现C. Auris 甘露聚糖含有额外的甘露糖磷酸（Mα1-PO 4）分支，这是该物种所特有的。这是一 非常令人兴奋和潜在的非常重要的新发现C.耳具有甘露聚糖外层 它在结构上不同于所有其他念珠菌属物种，实际上，任何其他真菌病原体，表明 Mα1-PO 4结构区别于C.耳内其他真菌病原体。在这一点上，几乎没有什么是 我们对控制这种独特的细胞壁表型表达的基因的了解。In C.白色念珠菌 Mnt 3、Mnt 5和Mnn 4蛋白是负责磷酸甘露聚糖的磷酸甘露糖基转移酶 生物合成此外，还有七种Mnn 4样蛋白，它们与Mnn 4在功能上是冗余的，但在功能上与Mnn 4相似。 在磷酸甘露聚糖生物合成中不起主要作用。念珠菌基因组数据库的调查显示， 梭除了5个MNN 4样基因外，auris还含有MNT 3、MNT 5和MNN 4基因。由于 C. auris的优势种为C.我们假设MNT 3，MNT 5和 MNN 4基因在磷酸甘露聚糖生物合成中保持保守的作用，而五个MNN 4基因中的一个或多个在磷酸甘露聚糖生物合成中保持保守的作用。 MNN 4样基因已经分化产生影响Mα1-PO 4分支和/或 磷酸化我们将通过构建C. Auris 为了确定它们是否影响磷酸甘露聚糖的生物合成和M1α-PO 4分支的添加，使用高 现场核磁共振此外，我们将确定这些突变体是否增加或减少了对 人巨噬细胞及其杀死巨噬细胞的能力。从这项工作中，我们期望开发出一种更好的 了解C.耳。生成的数据将有助于为潜在的诊断服务， 以及疫苗的发展。

Candida auris is a recently emergent fungal pathogen. This newly emergent species has risen worldwide over the last ten years since its first recognition in Japan.This organism has become a public health problem due to its antifungal resistance and its ability to persist in critical care and nursing home facilities. One of the reasons behind this ability to persist is that many of the clinical isolates show multidrug resistance and, in rare cases, can be pan-resistant. Recently we examined the cell wall of eight C. auris isolates and discovered that C. auris mannans contain additional mannosyl phosphate (Mα1-PO4) branching that is unique to this species. This is a very exciting and potentially very important new finding. The fact that C. auris has an outer coating of mannan that is structurally distinct from all other Candida species and, indeed, any other fungal pathogen, suggests that the Mα1-PO4 structure distinguishes C. auris from other fungal pathogens. At this point, virtually nothing is known about the genes which control the expression of this unique cell wall phenotype. In C. albicans the Mnt3, Mnt5, and Mnn4 proteins are phosphmannosyltransferases responsible for phosphomannan biosynthesis. In addition there are seven Mnn4-like proteins that are functionally redundant with Mnn4 but do not play a major role in phosphomannan biosynthesis. A survey of the Candida Genome Database revealed that C. auris also contains the MNT3, MNT5, and MNN4 genes in addition to five MNN4-like genes. Due to the similarities of the genes in C. auris to those of C. albicans we hypothesize that the MNT3,MNT5 and MNN4 genes maintain a conserved role in phosphomannan biosynthesis, while one or more of the five MNN4-like genes have diverged to produce proteins that impact the Mα1-PO4 branching and/or phosphorylation. We will assess the role that these genes play via construction of deletion mutants in C. auris to determine if they impact phosphomannan biosynthesis and the addition of M1α-PO4 branching, using high field NMR. In addition we will determine if these mutants have increased or decreased attractiveness to human macrophages and their ability to kill the macropahges. From this work we expect to develop a better understanding of mannan biosynthesis in C. auris. The data generated will help to serve potential diagnostic and vaccine development in the future.