Identifying new genes for branchio-oto-renal syndrome

描述（由申请方提供）：鳃-耳-肾综合征新基因的鉴定。鳃耳肾综合征（BOR）是一种常染色体显性遗传的发育障碍，其特征是听力损失、肾脏异常和鳃弓缺陷。鳃-耳综合征（BO）是一种无肾脏异常的相关疾病。果蝇眼睛缺失基因（EYA 1）的人类直系同源基因中的显性突变导致BOR和BO。 通过全基因组连锁搜索在一个大的家族的18个人受BO影响，我们映射到染色体14 q21的一个新的基因位点（BOS 3）。在33 Mb的关键遗传区间内，我们定位了SIX 1基因，该基因已知在肾脏和耳朵器官发生的PAX-EYA-SIX发育调控层次中发挥作用。通过直接测序，我们在该家系和另外2个BOR/BO家系中鉴定出3种不同的SIX 1突变，从而鉴定出SIX 1是引起BOR和BO的新基因。通过功能分析，我们表明，所有3个突变干扰Eya 1-Six 1蛋白质-蛋白质相互作用，两个同源结构域突变阻碍Six 1-DNA结合。 此外，我们首次发现SOX 13突变可能存在于BOR/BO患者中。梭elegans INTERACTOME项目最近证实了Eya-1/six-1相互作用，并在该模式生物中鉴定了许多其他Eya-1相互作用伴侣，其人类直系同源物代表了BOR/BO的优秀候选基因。 该提议旨在鉴定引起BOR/BO的其他基因、突变，以及在BOR/BO和人类肾脏和耳部发育背景下SIX 1、SOX 13和相关基因的功能表征。 具体而言，我们建议： 1)检测新发现的BOR/BO基因SIX 1和SOX 13中的进一步突变，并研究它们在BOR/BO中对肾脏和耳部发育缺陷的功能作用。 2)进一步鉴定负责BOR/BO的基因，使用Eya 1/Six 1转录复合物的成员和来自C. elegans相互作用数据，并研究基因型/表型关系。 3)在一个新的BOR/BO大家族中通过定位克隆鉴定一个新的引起BO的基因。鳃耳肾综合征新基因的发现将为听力缺陷、泌尿道畸形以及肾和耳发育的病理机制提供新的见解。

DESCRIPTION (provided by applicant): Identification of new genes for branchio-oto-renal syndrome. Branchio-oto-renal syndrome (BOR) is an autosomal dominant developmental disorder characterized by the association of hearing loss, renal anomalies, and branchial arch defects. Branchio-otic syndrome (BO) is a related disorder without renal anomalies. Dominant mutations in the human ortholog of the Drosophila eyes absent gene (EYA1) cause BOR and BO. By total genome search for linkage in a large kindred of 18 individuals affected with BO, we mapped a new gene locus (BOS3) to chromosome 14q21. Within the 33 Mb critical genetic interval we located the SIX1 gene, which is known to play a role in the PAX-EYA-SIX hierarchy of developmental regulation in the organogenesis of kidney and ear. By direct sequencing we identified 3 different SIX1 mutations in this kindred and in 2 additional kindred with BOR/BO, thus identifying SIX1 as a new gene causing BOR and BO. By functional analysis we show that all 3 mutations interfere with Eya1-Six1 protein-protein interaction, and that the two homeodomain mutations impede Six1-DNA binding. In addition, we generated first evidence that SOX13 mutations may be found in patients with BOR/BO. The C. elegans INTERACTOME project recently confirmed eya-1/six-1 interaction and identified in this model organism many further eya-1 interaction partners, the human orthologs of which represent excellent candidate genes for BOR/BO. This proposal is aimed at the identification of further genes, mutations in which cause BOR/BO and at the functional characterization of SIX1, SOX13, and related genes within the context of BOR/BO and kidney and ear development in humans. Specifically, we propose to: 1) Detect further mutations in the newly identified BOR/BO genes SIX1 and SOX13, and study their functional role for kidney and ear developmental defects in BOR/BO. 2) Identify further genes as responsible for BOR/BO, using as candidate genes members of the Eya1/Six1 transcriptional complex and eya-1 binding partners derived from the C. elegans INTERACTOME data, and study genotype/phenotype relationships. 3) Identify a new gene causing BO by positional cloning in a new large BOR/BO kindred. Identification of new genes causing branchio-oto-renal syndrome will offer new insights into the pathomechanisms of hearing defects, urinary tract malformations as well as kidney and ear development.