Oscillatory gene expression and the maintenance of temporal patterning

项目摘要： 发育基因调控是一个多维度的问题，其中信号会聚以产生基因调控的模式。 转录在适当的位置（空间调节）和正确的时间（时间调节）。一个同样 这个调控过程的一个重要特征是在转录过程中产生正确的转录量。 由于许多关键调控基因以剂量敏感的方式发挥作用， 表达可导致发育缺陷或疾病。目前我们只有初步的了解 关于发育调控基因的转录输出是如何建立的。实验概述于 该建议旨在通过采用C中的体内成像系统直接解决该问题。秀丽线虫幼虫 其中GFP分子直接与新生RNA连接，同时它们在细胞中被积极转录。 原子核这个新平台使我们能够直接量化和建模实时表达动态， 最终决定了个体基因在整个发育过程中的转录输出。在目标1中，我们将使用 系统来剖析两种转录因子BLMP-1和LIN-42调节细胞凋亡特征的机制。 转录爆发（包括爆发频率，持续时间和幅度），以调节关键的转录水平， microRNA（包括lin-4和let-7）决定细胞命运规范的顺序模式。然后我们会调查 BLMP-1通过重塑启动未来转录的基因组和分子机制 靶基因位点附近的染色质可及性。在最后的目标中，我们将描述物理和功能 LIN-42与几种保守的核激素受体（NHR-23 ROR γ和NHR-85 Rev-1）之间的相互作用。 erbβ）介导lin-4和let-7转录激活的时间方面。这项研究将揭示 染色质重塑的原理及其对调节周期性转录输出的影响 表达的基因确保了开发期间细胞命运规格的精确性和稳健性。

Project Abstract: Developmental gene regulation is a multidimensional problem where signals converge to generate patterns of transcription at the proper location (spatial regulation) and correct time (temporal regulation). An equally important feature of this regulatory process involves generating the correct amount of transcription during development as many key regulatory genes function in dosage sensitive manners where too much or too little expression can lead to developmental defects or disease. At present, we have only a primitive understanding about how the transcriptional output of developmentally regulated genes is established. Experiments outlined in this proposal aim to directly address this problem by employing an in vivo imaging system in C. elegans larva where GFP molecules are directly tethered to nascent RNAs while they are being actively transcribed in the nucleus. This new platform enables us to directly quantify and model the real-time expression dynamics that ultimately dictate transcriptional output of individual genes throughout development. In Aim 1, we will use this system to dissect the mechanisms by which two transcription factors, BLMP-1 and LIN-42, modulate features of transcriptional bursting (including burst frequency, duration, and amplitude) to tune transcriptional levels of key microRNAs (including lin-4 and let-7) that dictate sequential patterns of cell fate specification. We will then probe the genomic and molecular mechanisms that BLMP-1 employs to prime future transcription by remodeling chromatin accessibility near target gene loci. In the final Aim, we will characterize the physical and functional interactions between LIN-42 and several conserved nuclear hormone receptors (NHR-23RORγ and NHR-85Rev- erbβ) that mediate temporal aspects of lin-4 and let-7 transcriptional activation. This avenue of research will reveal the principles by which chromatin remodeling and its impact on modulating the transcriptional output of cyclically expressed genes ensures the precision and robustness of cell fate specification during development.