Analyzing allele specific gene expression and regulation in C. albicans.

描述(申请人提供)：背景：大多数真核生物是杂合子，由两个不同的等位基因组成。然而，关于不同的等位基因是如何差异表达和调控的，以及差异调控是否能赋予生物体适合性，人们知之甚少。这些研究将为等位基因特异性表达的程度、机制和功能提供重要的信息。这些主题与理解癌症的机制高度相关。目的/假设：白色念珠菌的天然杂合性使其能够进化并适应在其哺乳动物宿主中茁壮成长。然而，等位基因差异表达的程度及其调控机制尚未完全阐明。我建议确定差异等位基因表达的程度，并阐明在真菌二态条件下特定转录因子的差异结合是否调节这种差异等位基因表达。这项工作有望对真核生物杂合性的范围和作用提供总体上的见解。具体目标：1)全面检测白色念珠菌的差异等位基因表达程度。2)确定差异基因表达是否与Poll I和转录因子结合的差异有关。3)检测差异调节等位基因的功能。研究设计：以白色念珠菌为模型系统，研究差异等位基因的表达和调控。我将使用454种DNA测序方法来全局分析等位基因特定的基因表达。ChlPSeq.(染色质免疫沉淀和测序)将被用来评估有多少是由于转录调控。最后，我将使用基因置换的方法来确定差异等位基因表达的功能。 相关性：癌症的一个特征是基因组不稳定。这可能是由低甲基化和/或杂合性丧失引起的。此外，特定的染色体和特定的染色体区域被优先扩增是很常见的。因此，基本了解等位基因特异性表达的多样性以及如何控制它对癌症来说是非常重要的。此外，白念珠菌是一种机会性病原体，影响包括癌症在内的许多疾病。了解肿瘤细胞生长的调控机制，进而转化为二相性生长，对癌症患者的治疗具有重要意义。

DESCRIPTION (provided by applicant): Background: Most eukaryotes are heterozygous, comprised of two distinct alleles. However, little is known about how distinct alleles are differentially expressed and regulated and whether differential regulation can confer fitness to an organism. The proposed studies will provide important information as to the extent of allele specific expression, its mechanisms and function. These topics are highly relevant to understanding mechanisms of cancer. Objective/hypothesis: The natural heterozygosity of C. albicans has allowed it to evolve and adapt to thrive in its mammalian host. However, the degree of differential allelic expression and the mechanism of its regulation are yet to be fully elucidated. I propose to determine the extent of differential allelic expression, and to elucidate if differential binding of specific transcription factors under fungal dimorphic conditions regulates this differential allelic expression. This work is expected to provide insights into the extent and role of heterozygosity of eukaryotes in general. Specific Aims: 1) Globally examine the extent of differential allelic expression in Candida albicans. 2) Determine if differential gene expression is associated with differences in binding of Poll I and transcription factors. 3) Assay the function of differentially regulated alleles. Study Design: I plan to study differential allelic expression and regulation using C. albicans as a model system. I will use 454 DNA sequencing methods to globally analyze allele specific gene expression. ChlPSeq. (chromatin immunoprecipitation and sequencing) will be used to assess how much is due to transcriptional regulation. Finally, I will determine the function of differential allelic expression using gene replacement methods. Relevance: A hallmark of cancer is genome instability. This can be caused by hypomethylation and/or loss of heterozygosity. Moreover, it is common for specific chromosomes and specific chromosomal regions to be preferentially amplified. Thus, basic understanding of the diversity of allele specific expression and how it can be controlled is of high importance to cancer. Moreover, C. albicans is an opportunistic pathogen that affects many diseases, including cancer. Understanding mechanisms that control its growth and switch to dimorphic growth, which is involved in pathogenesis, is of significance for treatment of cancer patients.