Molecular studies of Noonan syndrome and related disorders

描述(申请人提供)：Noonan和Leopard综合征(NS和LS)是常染色体显性特征，特征包括先天性心脏病(CHD)、身材矮小、畸形和智力低下；LS还包括扁豆。我们已经证明，PTPN11错义突变导致近50%的NS，并导致其蛋白酪氨酸磷酸酶SHP-2的功能增强。功能丧失的PTPN11突变导致LS。最近，我们发现KRAS突变导致1%的NS。SHP-2和KRAS在Ras丝裂原活化蛋白激酶(MAPK)信号转导中起作用。特异性AIM 1将验证未知NS基因编码Ras-MAPK信号蛋白的假设。候选基因将以高通量的方式与大量没有PTPN11或KRAS突变的NS受试者进行重新测序。将使用生化和细胞培养方法来测试突变对新NS基因的影响。在特定的AIM 2中，我们假设SHP-2突变通过对发育的功能获得影响而导致豹子综合征，尽管它们的磷酸酶活性降低，并且NS相关的KRAS突变比NS PTPN11缺陷更深刻地改变信号。为了验证这些想法，我们将产生诱导表达同源NS和LS突变蛋白的转基因果蝇。他们的表型和遗传相互作用将被描述。此外，我们假设，从现有的NS果蝇模型中，与EGFR相关的翅型在遗传上相互作用的基因将识别新的信号转导方面以及新的NS疾病基因。将进行敏化筛选，以确定抑制或增强该翅膀表型的基因。

DESCRIPTION (provided by applicant): Noonan and LEOPARD syndromes (NS and LS) are autosomal dominant traits with features that include congenital heart disease (CHD), short stature, dysmorphism, and mental retardation; LS also includes lentigines. We have shown that PTPN11 missense mutations cause nearly 50% of NS and engender gain-of- function on its protein, the protein tyrosine phosphatase SHP-2. Loss-of-function PTPN11 mutations cause LS. Recently, we found that KRAS mutations cause 1% of NS. SHP-2 and KRAS play roles in RAS-mitogen activated protein kinase (MAPK) signaling. SPECIFIC AIM 1 will test the hypothesis that the unknown NS genes encode proteins in RAS-MAPK signaling. Candidate genes will be resequenced in a high throughput fashion with a large cohort of NS subjects without PTPN11 or KRAS mutation. Biochemical and cell culture approaches will be used to test the effects of mutations on novel NS genes. In SPECIFIC AIM 2, we hypothesize that SHP-2 mutants cause LEOPARD syndrome through gain-of-function effects on development despite their reduced phosphatase activity and that NS-associated KRAS mutations alter signaling more profoundly than do NS PTPN11 defects. To test these ideas, we will generate transgenic fruit flies inducibly expressing homologous NS and LS mutant proteins. Their phenotypes and genetic interactions will be characterized. Further, we hypothesize that genes interacting genetically with the Egfr-related wing phenotype from the existing NS fruit fly model will identify novel aspects of signal transduction as well as new NS disease genes. A sensitized screen will be performed to identify genes that suppress or enhance that wing phenotype.