Early Muscle Cell Fate Determination During Embryogenesis

胚胎发生过程中早期肌细胞的命运决定

• 批准号: 9506346
• 负责人: Judith Venuti
• 金额: $ 22.42万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-01 至 1998-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9506346&HistoricalAwards=false
• 关键词: Early; Muscle; Cell; Fate; Determination

9506346 Venuti Studies on the MyoD family of muscle specific gene regulatory factors have provided enormous insight into the mechanisms that regulate myoblast determination and differentiation. But a fundamental question that remains in muscle developmental biology is: what activates the myogenic transcription factors? The prime objective of this proposed research is to identify the earliest molecular events that commit a pluripotent mesodermal stem cell to a myogenic fate. These experiments are designed to identify factors that influence early embryonic muscle cell determination and explore the capacity of embryonic cells which are not part of the myogenic program to differentiate as muscle cells. The sea urchin embryo, whose development is extremely well understood and whose embryos are particularly amenable to micromanipulation during early development, will be the experimental organism. Dr. Venuti has developed an in vitro assay that will enable her to ask if and when extracellular signaling is required for the determination and differentiation of muscle precursors or if they develop cell autonomouqly. These experiments should identify the signals or cues that initiate the decision to follow a muscle fate and determine when muscle progenitors first become committed. Dr. Venuti has cloned and characterized the muscle specific basic helix-loop-helix (b-HLH) transcription factor, SUM-1, from the sea urchin embryo and shown that it is activated very early in the muscle differentiation program. She has shown that SUM-1 can activate muscle specific reporter elements in vertebrate tissue culture cells and in microinjected sea urchin embryos. She will examine the consequences of expressing SUM-1 at premature times and at ectopic locations in the embryo either alone or in combination with interacting factors. To identify factors that act directly to regulate the transcription of SUM-1, the cis regulatory elements and trans acting factors of the SUM-1 promoter wil l be characterized. Once important temporal and spatial regulatory elements of the SUM-1 promoter are identified, she will test the effects of the extracellular signals identified in in vitro assays on these elements. The combination of these experiments will help direct long term investigations into muscle cell fate determination and the role of extracellular signals in the decision of embryonic cells to commit to a myogenic fate. They will also provide a better understanding of the role of the myogenic transcription factor, SUM-1, and other regulatory molecules in these determination events. ***

小行星9506346 对肌肉特异性基因调节因子MyoD家族的研究为调节成肌细胞决定和分化的机制提供了巨大的见解。但是，肌肉发育生物学中仍然存在一个基本问题：是什么激活了生肌转录因子？这项研究的主要目的是确定最早的分子事件，使多能中胚层干细胞的肌源性命运。这些实验旨在鉴定影响早期胚胎肌细胞确定的因素，并探索不属于肌生成程序的胚胎细胞分化为肌细胞的能力。海胆胚胎将成为实验生物体，其发育过程非常清楚，其胚胎在早期发育过程中特别适合显微操作。Venuti博士开发了一种体外试验，使她能够询问细胞外信号是否以及何时需要用于肌肉前体的确定和分化，或者它们是否发育成细胞。这些实验应该确定启动决定遵循肌肉命运的信号或线索，并确定肌肉祖细胞何时首次定型。Venuti博士从海胆胚胎中克隆并鉴定了肌肉特异性碱性螺旋-环-螺旋（b-HLH）转录因子SUM-1，并表明它在肌肉分化程序的早期被激活。她已经证明SUM-1可以激活脊椎动物组织培养细胞和显微注射海胆胚胎中的肌肉特异性报告元件。她将研究SUM-1在胚胎中过早表达和异位位置表达的后果，无论是单独还是与相互作用的因素结合。 为了鉴定直接调节SUM-1转录的因子，将表征SUM-1启动子的顺式调节元件和反式作用因子。一旦确定SUM-1启动子的重要时间和空间调控元件，她将测试在体外测定中确定的细胞外信号对这些元件的影响。这些实验的结合将有助于指导对肌细胞命运决定和细胞外信号在胚胎细胞决定肌源性命运中的作用的长期研究。他们也将提供一个更好的理解的作用，生肌转录因子，SUM-1，和其他调节分子在这些决定事件。 ***