Dominant-negative GCMB mutations cause hypoparathyroidism

显性阴性 GCMB 突变导致甲状旁腺功能减退症

基本信息

批准号：
8101915
负责人：
Michael Mannstadt
金额：
$ 16.02万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-07-15 至 2013-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8101915
关键词：
Ablation Adult Affect Alleles Amino Acid Sequence Amino Acids Binding Binding Sites Biological Assay Biology C-terminal Calcium Candidate Disease Gene Cell Culture Techniques Cells DNA Data Development Disease Dominant-Negative Mutation Embryonic Development Endocrine System Diseases Etiology Exons Failure Family Family member Future Gene Targeting Gland Goals Homeostasis Homologous Gene Hormones Human Hypercalcemia Hyperparathyroidism Hypocalcemia result Hypoparathyroidism In Vitro Incidence Lead Location Luciferases Mus Mutation Neuroglia Nucleic Acid Regulatory Sequences Nucleotides Open Reading Frames Orthologous Gene Parathyroid gland Patients Peptide Sequence Determination Production Promoter Regions Property Proteins Regulation Reporter Research Research Personnel Role Secondary Hyperparathyroidism Silicon Dioxide Small Interfering RNA Structure Structure of parathyroid chief cell Technology Therapeutic Time Transactivation base bone health bone metabolism calcium phosphate chromatin immunoprecipitation gland development improved loss of function mutation member mutant novel overexpression programs transcription factor

项目摘要

DESCRIPTION (provided by applicant): GCMB is a transcription factor that is exclusively expressed in parathyroid cells and that is necessary for parathyroid gland development. These glands produce parathyroid hormone (PTH), which is one of the most important regulators of calcium homeostasis and bone metabolism. My long-term goal is to elucidate the role(s) of GCMB in the mature parathyroid gland and its potential for use in therapeutic strategies to treat primary and secondary hyperparathyroidism. Mice with homozygous ablation of Gcm2, one of the two mammalian orthologs, lack parathyroid glands and develop hypocalcemia and hyperphosphatemia. Consistent with these findings in mice, a homozygous deletion within GCMB, the human homolog of Gcm2, was previously revealed as a cause of an autosomal recessive form of hypoparathyroidism. I have now identified heterozygous GCMB mutations in the affected, but not the unaffected members of two unrelated families with autosomal dominant hypoparathyroidism. Both heterozygous GCMB mutations are single nucleotide deletions within GCMB exon 5 that introduce changes within the C-terminal portion of GCMB, which contains the putative transactivation domain. The deletions lead to a shift in open reading frame at amino acid residues 463 and 467, respectively, and the addition of 65 and 63 amino acids, respectively, of unrelated protein sequence. Preliminary data demonstrate that the mutant forms of GCMB inhibited the actions of the wild-type protein on a luciferase reporter construct in vitro suggesting that the mutant GCMB has dominant-negative properties. To explore the underlying mechanisms leading to impaired PTH synthesis and secretion, I will determine the mechanism through which heterozygous GCMB mutations cause autosomal-dominant hypoparathyroidism (Aim 1), using a GCMB-responsive reporter in vitro, and whether the identified dominant-negative GCMB mutants affect PTH synthesis and secretion in primary parathyroid cell cultures (Aim 2). Furthermore, I will investigate additional members of the two families with autosomal dominant hypoparathyroidism, and I will identify the natural target genes for GCMB(Aim 3). Parathyroid glands produce parathyroid hormone (PTH), which is necessary for calcium regulation and bone health. In two families with insufficient parathyroid gland activity, we have identified mutations in GCMB, a factor necessary for the development of parathyroid glands. The characterization of these mutations will help improve our understanding of parathyroid gland biology.

描述（由申请人提供）： GCMB是在甲状旁腺细胞中仅表达的转录因子，这对于甲状旁腺发育是必不可少的。这些腺体产生甲状旁腺激素（PTH），这是钙稳态和骨代谢的最重要的调节剂之一。我的长期目标是阐明GCMB在成熟的甲状旁腺中的作用及其在治疗治疗原发性和继发性甲状旁腺功能亢进症的治疗策略中的潜力。 GCM2纯合消融的小鼠是两种哺乳动物直系同源物之一，缺乏甲状旁腺，发展低钙和高磷酸血症。与这些发现在小鼠中的发现一致，GCMB内的纯合缺失（人类GCM2的人类同源物）先前被揭示为甲状腺功能体性甲状旁腺功能小体隐性形式的原因。我现在已经确定了受影响的杂合子GCMB突变，但没有在两个无关的患有常染色体显性甲状旁腺功能亢进症的无关家族的不受影响的成员中。两个杂合GCMB突变都是GCMB外显子5中的单核苷酸缺失，它在GCMB的C末端部分中引入了变化，其中包含推定的反式激活域。缺失分别导致氨基酸残基463和467处的开放阅读框的变化，分别添加了无关蛋白质序列的65和63个氨基酸。初步数据表明，GCMB的突变形式在体外抑制了野生型蛋白对荧光素酶报告基因构建体的作用，这表明突变体GCMB具有显性阴性特性。要探索导致PTH综合和分泌受损的潜在机制，我将确定杂合性GCMB突变引起的机制，引起常染色体抑制性抗心理学，使用GCMB反应性的报道剂在体外和确定的占主导地位的综合概念中，使用GCMB反应性的报道器是否影响了ptrovial-nect contys contys contys contys in night prontrion conty contints conty in nigation conntrions是否构成了ptrotir contririon connints in文化（目标2）。此外，我将调查两个患有常染色体显性甲状旁腺功能亢进症的家庭的其他成员，我将确定GCMB的天然靶基因（AIM 3）。甲状旁腺产生甲状旁腺激素（PTH），这是钙调节和骨骼健康所必需的。在两个甲状旁腺活性不足的家族中，我们已经确定了GCMB中的突变，这是甲状旁腺发展所必需的因素。这些突变的表征将有助于提高我们对甲状旁腺生物学的理解。