Regulation of cardiac gene expression by MEF2-Myocardin transcription complexes

MEF2-Myocardin 转录复合物对心脏基因表达的调节

• 批准号: 8590744
• 负责人: Brian L Black
• 金额: $ 41.16万
• 依托单位: J. DAVID GLADSTONE INSTITUTES
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8590744
• 关键词: 5' -AMP-activated protein kinase; Adult; Binding; Binding Sites; Biochemical; Bioinformatics; Boxing; Cardiac; Cardiovascular Diseases; Catalytic Domain; Cell Culture Techniques; Complex; Congenital Abnormality; Congenital Heart Defects; Development; Dimerization; Embryo; Energy-Generating Resources; Enhancers; Fatty Acids; Gene Activation; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Glycolysis; Heart; Heart Hypertrophy; Heart failure; Homeostasis; Individual; Instruction; Knock-out; Maps; Mass Spectrum Analysis; Metabolism; Play; Positioning Attribute; Protein Isoforms; Proteomics; Regulation; Research Personnel; Role; Signal Transduction; Site; Specificity; Time; Tissues; Transcription Coactivator; Transcriptional Regulation; Transgenic Mice; Transgenic Organisms; Work; base; cis acting element; cofactor; energy balance; glucose metabolism; heart metabolism; in vivo; mortality; myocardin; novel; response; transcription factor; transcriptome sequencing

Cardiovascular disease is the most common cause of mortality in adults, and congenital heart defects are the most common form of birth defects in the US. AMP-activated protein kinase (AMPK) is a master regulator of energy balance and homeostasis and plays a central role in the switch from fatty acids to glycolysis during cardiac hypertrophy and heart failure. AMPKa2 is the predominant isoform ofthe catalytic subunit expressed in the heart and is encoded by the Prkaa2 gene. Although AMPK and its role in metabolism and heart failure have been extensively studied, the transcripfional control ofthe genes encoding AMPK subunits is completely unknown. The MADS box transcription factor MEF2C is required for cardiac development and functions as a signal responsive transcription factor that interacts with a variety of cofactors to either negatively or positively regulate transcription. The most potent transcriptional coactivator for MEF2C is the SAP domain transcripfional regulator Myocardin. MEF2C specifically interacts with Myocardin-93S, which is highly enriched in the heart, yet the transcripfional targets and mechanisms of synergy facilitated by the Myocardin-MEF2 complex have not been identified. Preliminary studies found that the Prkaa2 gene is a direct transcripfional target ofthe MEF2C-Myocardin complex via a novel cardiac- specific enhancer. This enhancer contains two bona fide MEF2 binding sites that function together in a multiplicative fashion in response to Myocardin-93S and MEF2C. Although transcripfional synergy is frequently observed in many contexts and is a well-described phenomenon, the role of cis-acting elements, their position, spacing, and sequence in facilitating synergy have been far less well described. Using transgenic mouse, cell culture, biochemical, and mass spectrometry approaches, this work will define determinants of MEF2-Myocardin transcripfional synergy, will identify additional interaction partners for MEF2C and Myocardin through interactome mapping, and will identify in vivo targets ofthe Myocardin-MEF2 complex. This work will also determine the upstream regulation of Prkaa2 for the first time. This work may provide additional strategies for manipulating AMPK expression during heart failure.

心血管疾病是成人死亡的最常见原因，先天性心脏病是美国最常见的出生缺陷形式。 AMP 激活蛋白激酶 (AMPK) 是能量平衡和稳态的主要调节因子，在心脏肥大和心力衰竭期间从脂肪酸向糖酵解的转变中发挥着核心作用。 AMPKa2 是心脏中表达的催化亚基的主要亚型，由 Prkaa2 基因编码。尽管 AMPK 及其在代谢和心力衰竭中的作用已被广泛研究，但编码 AMPK 亚基的基因的转录控制却完全未知。 MADS 盒转录因子 MEF2C 是心脏发育所必需的，并且作为信号响应转录因子发挥作用，与多种辅助因子相互作用以负向或正向调节转录。 MEF2C 最有效的转录共激活因子是 SAP 域转录调节因子 Myocardin。 MEF2C 与心肌中高度富集的 Myocardin-93S 特异性相互作用，但 Myocardin-MEF2 复合物促进的转录靶点和协同机制尚未确定。初步研究发现，Prkaa2 基因是 MEF2C-Myocardin 复合物通过新型心脏特异性增强子的直接转录靶标。该增强子包含两个真正的 MEF2 结合位点，它们以乘法方式共同发挥作用，响应 Myocardin-93S 和 MEF2C。尽管转录协同作用在许多情况下经常被观察到并且是一种得到充分描述的现象，但顺式作用元件、它们的位置、间隔和序列在促进协同作用中的作用却远没有得到很好的描述。利用转基因小鼠、细胞培养、生化和质谱方法，这项工作将定义 MEF2-Myocardin 转录协同作用的决定因素，将通过相互作用组图谱确定 MEF2C 和 Myocardin 的其他相互作用伙伴，并将确定 Myocardin-MEF2 复合物的体内靶标。这项工作也将首次确定 Prkaa2 的上游调控。这项工作可能为心力衰竭期间操纵 AMPK 表达提供额外的策略。