DNA helicase functions in genome maintenance

描述（由申请人提供）：内聚因子突变与出生缺陷、严重认知障碍、细胞非整倍性和癌症密切相关。目前，不同类别的内聚因子（内聚蛋白系链、沉积复合物和建立因子）内的突变被认为导致不同的发育疾病：内聚蛋白和沉积突变引起科尔内利亚德兰格综合征（CdLS），而建立突变引起罗伯茨综合征（RBS）。这些出生缺陷的分子基础也被认为是分开的，尽管这些多谱疾病的性质非常相似：CdLS由转录失调引起，RBS由祖细胞凋亡损失引起。我们首先确定，现在已经确定了第三类凝聚力的因素-Chl 1 DNA解旋酶。人类Chl 1（ChlR 1/DDX 11）的突变导致另一种多谱发育障碍，称为华沙断裂综合征（WABS），其具有在CdLS和RBS中发现的许多特征（认知障碍，颅/面部异常，生长迟缓，耳聋，心脏缺陷和肢体障碍）。 在我们的研究过程中，我们发现Chl 1既与建立因子Eco 1相互作用，又是cohesin和cohesin沉积复合物向DNA募集所必需的。由此，我们假设WABS、CdLS和RBS实际上是仅通过潜伏期和严重程度区分的单一疾病状态。目前，Chl 1 DNA解旋酶是唯一的基础环节，通过它可以研究所有三种疾病的总和。尽管Chl 1的关键（和临床）性质，很少有人知道它的调节，作用位点或对染色质结构的影响。 在这个建议中，我们使用遗传，分子和生物化学的方法来利用Chl 1在芽殖酵母模型系统，以解决基本问题的保守途径相关的出生缺陷和人类的非整倍体。具体来说，我们建议阐明Chl 1在DNA复制过程中特异性地被招募到DNA的机制（特异性Aim 1），并确定Chl 1促进粘附素沉积活性的机制，重点是染色质结构（特异性Aim 2）。

DESCRIPTION (provided by applicant): Cohesion factor mutations are firmly situated at the nexus of birth defects, severe cognitive impairment, cell aneuploidy and cancer. Presently, mutations within different classes of cohesion factors (cohesin tethers, deposition complex and establishment factors) are thought to result in different developmental maladies: cohesin and deposition mutations give rise to Cornelia de Lange Syndrome (CdLS) while establishment mutations give rise to Roberts Syndrome (RBS). The molecular bases for these birth defects are also considered to be separate, despite the very similar nature of these multispectrum maladies: CdLS arising from transcription dysregulation, RBS arising from apoptotic loss of progenitor cells. We first identified and now have characterized a third class of cohesion factors - Chl1 DNA helicase. Mutations in human Chl1 (ChlR1/DDX11) leads to another multispectrum developmental disorder, termed Warsaw Breakage Syndrome (WABS) that share many features (cognitive impairment, cranio/facial abnormalities, growth retardation, deafness, heart defects and extremity impairments) found in both CdLS and RBS. In the course of our studies, we found that Chl1 both interacts with establishment factor Eco1 and is required for the recruitment to DNA of both cohesin and cohesin deposition complex. From this, we hypothesize that WABS, CdLS and RBS are in reality a single disease state differentiated only by penetrance and severity. Currently, Chl1 DNA helicase is uniquely placed as the founding link through which all three maladies can be studied in the aggregate. Despite the critical (and clinical) nature of Chl1, little is known regarding its regulation, site of action or impact on chromatin architecture. In this proposal, we use genetic, molecular and biochemical methodologies to exploit Chl1 in the budding yeast model system to address fundamental questions of conserved pathways relevant to both birth defects and aneuploidy in humans. Specifically, we propose to elucidate the mechanism through which Chl1 is recruited to DNA specifically during DNA replication (Specific Aim1) and identify the mechanism through which Chl1 promotes cohesin deposition activity, focusing on chromatin architecture (Specific Aim 2)