Specialized post-transcriptional mechanisms of gene expression in quiescence

静止期基因表达的转录后机制 视觉静止（G 0）是一种可逆的细胞周期停滞期，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调节因子， G 0细胞，揭示了常规翻译的抑制及其被非经典机制取代， 使特定的基因表达G 0的作用和生存。根据我们的数据，G 0细胞是由 引起不同基因表达的专门的转录后机制。G 0细胞会转换成一个基因 表达谱，其维持短暂的停滞状态，使得能够存活，并保留细胞的能力， 重新进入扩散。这允许重要的G 0功能：G 0耐药癌症干细胞的存活， 免疫细胞外渗、组织再生和休眠干细胞的发育。G 0在以下方面很重要 癌症和免疫，产生关键的细胞因子，以促进炎症和肿瘤的持久性。G 0差 尽管它具有医学意义。本研究的目的是探讨转录后 在体外和体内研究G 0的机制和调控基因表达，以了解G 0的作用和生存。 根据我们的研究结果，我们的研究的关键发现是，传统翻译是 被G 0信号抑制，并被非典型因子取代，这些非典型因子能够使 对生存至关重要。值得注意的是，这些非典型因素改变了翻译起始位点的选择，扩大了翻译起始位点的范围。 蛋白质组通过创建新的框架（PNAS 2014）。我们鉴定了非编码microRNA，相关的RNA蛋白， 复合物（RNP）和非经典翻译因子介导的选择表达的一些免疫和 G 0中的细胞状态调节因子（Molecular Cell 2016）。我们的数据揭示了信号的变化，修改RNP在 G 0以实现特异性基因表达，这允许靶向疾病中的耐药G 0（Biorxiv/ 418715）。我们的研究指出了重要的未被发现的调控层：核糖体的修饰，mRNA RNP和相关的非规范翻译。G 0转录后机制的表征， 将提供深入了解专门的基因表达和机制，在疾病的G 0生存。 未来5年的发展方向首先，分析，纯化，消耗，突变和生化分析 的snoRNA和核糖体，将绘制snoRNP和核糖体修饰，提供变化的见解， G 0期基因表达的翻译机制。第二，需要对mRNA进行修饰， 相关的调控RNP，非经典翻译因子，翻译的靶点和G 0中的独特起始位点 将被识别。这些数据将在体内进行验证，以揭示G 0翻译组，在翻译时扩展 框架，并将揭示影响G 0的作用和活力的基因表达的转录后机制。 影响这些研究揭示了对转录后机制的新见解，提供了核糖体图谱， 和mRNA修饰，和翻译框架在G 0，以及它们对G 0的作用和生存的疾病。

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.