Specialized post-transcriptional mechanisms of gene expression in quiescence

静止期基因表达的特殊转录后机制 视觉静止(G0)是一组可逆的、细胞周期停滞的阶段，它允许细胞避免 由于恶劣的条件或压力而死亡。我们的研究发现了强大的RNA调节器，以及在 G0细胞，揭示了对常规翻译的抑制以及它被非规范机制所取代 为G0角色和生存启用特定基因表达。根据我们的数据，G0细胞通过 专门的转录后机制，可以诱导不同的基因表达。G0细胞切换到一种基因 维持瞬时停滞状态、使细胞存活并保持细胞能力的表达谱 重新进入核扩散阶段。这允许重要的G0功能：G0耐药癌症干细胞存活， 通过休眠干细胞的免疫细胞外渗、组织再生和发育。G0在以下方面很重要 癌症和免疫，产生关键的细胞因子，促进炎症和肿瘤的持久性。G0很差 尽管它在医学上具有重要意义，但人们还是理解它。我的研究目的是调查转录后 G0在体外和体内的作用机制及其调控基因的表达，以了解G0的作用和生存。 基于我们的研究结果，我们研究的主要发现是，常规翻译是 被G0信号抑制，并被非规范因子取代，这些非规范因子允许特定的基因表达 对生存至关重要。值得注意的是，这些非规范因素改变了翻译起点的选择，扩大了 通过创建新的框架进行蛋白质组研究(PNAS 2014)。我们鉴定了非编码的microRNAs，相关的RNA-蛋白质 复合体(RNP)和非规范翻译因子，介导少数免疫和 G0中的细胞状态调节器(分子细胞2016)。我们的数据揭示了改变RNP的信号变化 G0以实现特定的基因表达，从而允许在疾病中靶向抗药性G0(BioRxiv/ 418715)。我们的研究指出了未被发现的调控的重要层面：核糖体的修饰，mRNAs 和RNP以及相关的非规范翻译。G0转录后机制的特征， 将提供对疾病中G0存活的特殊基因表达和机制的洞察。 未来5年的发展方向首先是分析、提纯、耗竭、突变和生化分析 将绘制snoRNPs和核糖体修饰图，提供对以下变化的见解 G0中基因表达的翻译机制。第二，对mRNAs进行必要的修改， G0中相关的调控RNP、非规范翻译因素、翻译目标和独特的起始位置 将会被确认。这些数据将在体内得到验证，以揭示G0翻译组，并在翻译时扩展 并将揭示影响G0角色和生存能力的基因表达的转录后机制。 Impact这些研究揭示了转录后机制的新见解，提供了核糖体图谱 和mRNA修饰，以及G0中的翻译框架，以及它们对G0角色和疾病存活率的影响。

Abstract Specialized post-transcriptional mechanisms of gene expression in quiescence Vision Quiescence (G0) is an assortment of reversible, cell-cycle arrested phases, that permits cells to avoid death due to harsh conditions or stress. Our studies uncovered powerful RNA regulators, and modifications in G0 cells, revealing inhibition of conventional translation and its replacement by non-canonical mechanisms to enable specific gene expression for G0 roles and survival. Based on our data, G0 cells are perpetuated by specialized post-transcriptional mechanisms that elicit distinct gene expression. G0 cells switch to a gene expression profile that maintains the transient arrested state, enables survival, and retains the ability of the cell to re-enter proliferation. This permits important G0 functions: survival of G0 drug resistant cancer stem cells, immune cell extravasation, tissue regeneration and development by dormant stem cells. G0 is important in cancer and immunity, producing critical cytokines to promote inflammation and tumor persistence. G0 is poorly understood despite its medical significance. The objective of my research is to investigate post-transcriptional mechanisms and regulated gene expression in G0 in vitro and in vivo to understand G0 roles and survival. Premise based on our research findings The key finding of our studies is that conventional translation is inhibited by G0 signals and replaced by non-canonical factors that enable specific expression of genes that are critical for survival. Significantly, such non-canonical factors alter translation start site selection, expanding the proteome by creating new frames (PNAS 2014). We identified noncoding microRNAs, associated RNA-protein complexes (RNPs), and non-canonical translation factors that mediate select expression of few immune and cell state regulators in G0 (Molecular Cell 2016). Our data revealed signaling changes that modify RNPs in G0 to enable specific gene expression, which allowed targeting of drug resistant G0 in disease (Biorxiv/ 418715). Our studies indicate important layers of undiscovered regulation: modification of ribosomes, mRNAs and RNPs and associated non-canonical translation. Characterization of G0 post-transcriptional mechanisms, will provide insights into the specialized gene expression and mechanisms that underlie G0 survival in disease. Directions in the next 5 years First, profiling, purifications, depletions, mutations, and biochemical analyses of snoRNAs and ribosomes, will map snoRNPs and ribosome modifications, providing insights on changes to the translation machinery underlying gene expression in G0. Second, required modifications on mRNAs, associated regulatory RNPs, non-canonical translation factors, translated targets and unique start sites in G0 will be identified. These data will be verified in vivo to uncover the G0 translatome, expanded at the translation frame, and will reveal post-transcriptional mechanisms of gene expression that impacts G0 roles and viability. Impact These studies uncover new insights into post-transcriptional mechanisms, provide a map of ribosome and mRNA modifications, and translation frames in G0, and their impact on G0 roles and survival in disease.