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Mesodermal cell fate specification in C. elegans

秀丽隐杆线虫中胚层细胞命运规范

基本信息

批准号：
9100768
负责人：
Jun Liu
金额：
$ 32.87万
依托单位：
CORNELL UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-09-02 至 2018-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The mesodermal germ layer gives rise to a variety of functionally important cell types, including striated and non-striated muscles as well as non-muscle cells. Understanding the regulatory mechanisms underlying mesoderm diversification has widespread implications in basic biology, stem cell biology and clinical research. The C. elegans postembryonic mesodermal lineage, the M lineage, provides unique advantages for studying mesoderm diversification at single cell resolution. The M lineage is derived from a single pluripotent precursor cell, the M mesoblast, which during hermaphrodite postembryonic development proliferates and produces six cell types: striated bodywall muscles (BWM), non-muscle coelomocytes (CC), and four classes of non-striated sex muscles. Both M and its descendants divide in a reproducible pattern, which is under both developmental and cell cycle control. The M lineage is thus ideally suited to investigating how different mesodermal fates are diversified from a single progenitor cell, how positional information is integrated with lineage-intrinsic information, and how diverse programs of asymmetric patterning, cell division timing and orientation, and cell fate specification are integrated. Our long-term goal is to understand the regulatory logic of M lineage diversification in mechanistic detail. During the previous and current funding periods, we have successfully conducted in-depth molecular genetic studies on signaling and transcriptional regulatory mechanisms involved in M lineage development. Our results have allowed us to begin to assemble the regulatory networks involved in the proper specification of BWM, CC and the precursor of the non-striated muscles, the sex myoblast (SM). Our identification and characterization of several transcription factors involved in these fate specification processes have also provided key insights into how these factors may function in similar processes in vertebrates and how their malfunction may be linked to certain human diseases. More importantly, these studies have provided us with reagents and exciting opportunities to address additional fundamental questions in developmental biology. In this proposal, we will exploit the M lineage to dissect mechanisms involved in the specification and proliferation of multi-potent progenitors (Aim 1) and mechanisms underlying the specification of different types of non- striated/smooth muscles (Aim 2). Because many of the factors that we have identified are conserved in vertebrates and our studies of them in the M lineage have contributed to the mechanistic understanding of their functions in general, we propose to molecularly identify and characterize two "new" factors critical for M lineage development (Aim 3). Finally, we are at the point to exploit the M lineage to dissect the connection between cell type- and stage-specific chromatin features and transcription factor action during cell fate specification and cell differentiation in vivo, an important area in developmental biology that we know very little about. We propose to address this question using the newly developed INTACT (isolation of nuclei tagged in specific cell types) method (Aim 4).

描述（由申请方提供）：中胚层产生多种功能重要的细胞类型，包括横纹肌和非横纹肌以及非肌细胞。了解中胚层多样化的调控机制在基础生物学、干细胞生物学和临床研究中具有广泛的意义。梭线虫胚后中胚层谱系，M谱系，为在单细胞分辨率下研究中胚层多样化提供了独特的优势。M谱系来源于单个多能前体细胞，M中胚层，其在雌雄同体胚后发育期间增殖并产生六种细胞类型：横纹体壁肌（BWM）、非肌肉体腔细胞（CC）和四类非横纹性肌。M及其后代都以可再生的模式分裂，这是在发育和细胞周期控制下。因此，M谱系非常适合于研究不同的中胚层命运如何从单个祖细胞多样化，位置信息如何与谱系内在信息整合，以及如何整合不对称模式，细胞分裂时间和方向以及细胞命运规范的多样化程序。我们的长期目标是了解M谱系多样化的机制细节的监管逻辑。在之前和当前的资助期间，我们成功地对M谱系发育中涉及的信号传导和转录调控机制进行了深入的分子遗传学研究。我们的研究结果使我们能够开始组装参与BWM，CC和非横纹肌的前体，性成肌细胞（SM）的适当规范的调节网络。我们对参与这些命运规范过程的几种转录因子的鉴定和表征也为这些因子如何在脊椎动物的类似过程中发挥作用以及它们的功能障碍如何与某些人类疾病联系起来提供了关键见解。更重要的是，这些研究为我们提供了试剂和令人兴奋的机会，以解决发育生物学中的其他基本问题。在本提案中，我们将利用M谱系来剖析参与多能祖细胞的特化和增殖的机制（目标1）以及不同类型的非横纹肌/平滑肌特化的潜在机制（目标2）。由于我们发现的许多因子在脊椎动物中是保守的，并且我们对它们在M谱系中的研究有助于从总体上了解它们的功能，因此我们建议从分子水平上识别和表征两个对M谱系发育至关重要的“新”因子（目标3）。最后，我们在这一点上利用M谱系解剖细胞类型和阶段特异性染色质特征和转录因子的作用在细胞命运规范和细胞分化在体内，在发育生物学的一个重要领域，我们知道得很少之间的联系。我们建议使用新开发的INTACT（分离特定细胞类型中标记的细胞核）方法来解决这个问题（目的4）。