A Schizosaccharomyces pombe Model of Birt-Hogg-Dube Syndrome

描述（由申请人提供）：本R21申请的重点是分裂酵母Schizosaccharomyces pombe （S. pombe）中的BHD基因同源性。Birt-Hogg-Dube综合征是一种常染色体显性遗传病，以皮肤错构瘤、肺囊肿、自发性气胸和肾细胞癌为特征。BHD基因的种系突变最近也在一个主要遗传的原发性自发性气胸（PSP）和大疱性肺病变的大型亲属中被发现。BHD失活导致疾病的细胞途径完全未知。然而，错构瘤也发生在至少四种其他肿瘤抑制基因（PTEN、TSC1、TSC2和LKB1）发生种系突变的患者中。这些基因的蛋白产物的缺失导致mTOR激酶的激活。S. pombe BHD同源基因编码了一个与人类BHD序列高度保守的蛋白。在已发表的研究中，我们证明了tsc1+或tsc2+基因缺失的s.p ombe在氨基酸摄取方面存在缺陷。在初步研究中，我们在S. pombe中产生了一个BHD突变体delta-bhd。我们发现delta-bhd S. pombe对蛋氨酸的毒性类似物具有抗性，表明蛋氨酸摄取减少。Delta-hbhd S. pombe在亮氨酸摄取方面也存在缺陷，这与delta-tsc1、delta-tsc2和delta-tor1突变体相似。基于这些数据，我们的中心假设是Bhd蛋白通过S. pombe的Tor1信号。我们提出以下具体目标。目的1：我们将确定Bhd是否与S. pombe中的Tsc1、Tsc2和Tor1在相同的途径中起作用。目的2：我们将确定导致bhd+基因保守突变的疾病对亮氨酸和蛋氨酸摄取的影响。目的3：我们将在酵母Bhd途径中识别出可以利用遗传筛选挽救蛋氨酸摄取缺陷的蛋白质。我们的长期目标是利用S. pombe模型来阐明人类BHD蛋白的功能。这可能为参与囊性肺疾病发病机制的细胞通路提供新的见解。总结。酵母模型可以提供有关人类疾病相关基因最重要的细胞功能的关键信息。Birt-Hogg-Dube （BHD）综合征是一种罕见的疾病，与肺囊肿、肺塌陷和肾癌相关。目前还不清楚BHD基因突变是如何导致人类疾病的。我们将使用一种新的BHD酵母模型来阐明BHD蛋白的功能。

DESCRIPTION (provided by applicant): This R21 application is focused on the BHD gene ortholog in the fission yeast Schizosaccharomyces pombe (S. pombe). Birt-Hogg-Dube (BHD) syndrome is an autosomal dominant disorder characterized by skin hamartomas, lung cysts, spontaneous pneumothorax, and renal cell carcinoma. A germline mutation in the BHD gene was also recently found in a large kindred with dominantly inherited primary spontaneous pneumothorax (PSP) and bullous lung lesions. The cellular pathway through which inactivation of BHD leads to disease is completely unknown. However, hamartomas also develop in patients with germline mutations in at least four other tumor suppressor genes (PTEN, TSC1, TSC2 and LKB1). Loss of the protein products of these genes results in activation of the kinase mTOR. The S. pombe BHD ortholog encodes a protein with high sequence conservation to human BHD. In published work, we demonstrated that S. pombe with deletion of the tsc1+ or tsc2+ genes have defects in amino acid uptake. In preliminary studies, we generated a BHD mutant in S. pombe, delta-bhd. We found that delta-bhd S. pombe are resistant to a toxic analog of methionine, suggesting decreased methionine uptake. Delta-hbhd S. pombe also have a defect in the leucine uptake, which is similar to delta-tsc1, delta-tsc2 and delta-tor1 mutants. Based on these data, our central hypothesis is that the Bhd protein signals through Tor1 in S. pombe. We propose the following specific aims. Aim 1: We will determine whether Bhd functions in the same pathway as Tsc1, Tsc2, and Tor1 in S. pombe. Aim 2: We will determine the effect of disease causing conserved mutations in the bhd+ gene on leucine and methionine uptake. Aim 3: We will identify proteins in the Bhd pathway in yeast that can rescue the methionine uptake defect using genetic screens. Our long- term goal is to use this S. pombe model to elucidate the functions of the human BHD protein. This may provide novel insights into cellular pathways involved in the pathogenesis of cystic lung diseases. Lay summary. Yeast models can provide key information about the most important cellular functions of human disease-associated genes. Birt-Hogg-Dube (BHD) syndrome is a rare disease associated with lung cysts, lung collapse, and kidney cancer. Nothing is currently known about how BHD gene mutations lead to human disease. We will use a novel yeast model of BHD to elucidate the function of the BHD protein.