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。G 0在免疫和癌症中至关重要，促进炎症和适应 然而，尽管G 0具有医学意义，但对其了解甚少。我们的研究 在G 0细胞中发现了强大的RNA调节剂和修饰，揭示了对常规RNA的抑制。 翻译及其被非经典机制取代，以使G 0作用的特异性基因表达成为可能 和生存。根据我们的数据，G 0细胞通过专门的转录后机制得以延续， 引发特异性基因表达，维持短暂的停滞状态，使G 0在应激中存活 条件，并保留了G 0细胞重新进入细胞周期和持续疾病的能力。这允许 重要的G 0功能：白血病等恶性肿瘤中的药物和免疫存活，免疫细胞外渗， 组织再生和发育。我们研究的目的是研究不同的转录后表达， G 0白血病细胞中的机制和基因表达，以了解G 0的作用和疾病的持续性。 本研究的主要发现是，传统翻译被G 0信号抑制， 通过非典型的因素，使特定的基因表达是至关重要的生存。值得注意的是， 这些非经典因子改变了翻译起始位点的选择，通过创造新的蛋白质来扩展蛋白质组。 frames（PNAS 2014）.我们鉴定了非编码RNA、相关的RNA-蛋白质复合物（RNP）和非编码RNA。 在G 0期介导少数免疫和细胞状态调节因子选择性表达的典型翻译因子 （Molecular Cell 2016）。我们的数据揭示了在G 0中修饰RNP的信号变化，以使特定的基因 表达，这允许靶向疾病中的耐药G 0（Genome Biol.2020）。我们的研究表明 未被发现的重要调控层：核糖体、mRNA和RNP的修饰以及相关的 非规范翻译（Science 2020，Nat. Commun. 2020，Science Adv.2022）。G 0的特征 转录后的变化，将揭示隐藏的机制，驱动G 0生存疾病的持久性。 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存活中基因表达的翻译机制。第二，对mRNA的修饰， G 0中的相关RNP、非经典翻译因子、翻译的靶标和独特起始位点将被 确定发现G 0 translatome，在翻译框架扩展。最后，这些将在 体内和患者样本，以揭示影响G 0作用和持久性的转录后机制。 影响这些研究将揭示G 0转录后机制的新见解，提供一个地图， 核糖体和RNA修饰，翻译框架，以及它们对G 0作用和疾病生存的影响。

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. G0 is critical in immunity and cancer, promoting inflammation and adaptations for disease persistence; however, G0 is poorly understood despite its medical significance. 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 specific gene expression, which maintains the transient arrested state, enables G0 survival in stress conditions, and retains the ability of G0 cells to re-enter the cell cycle and persist disease. This permits important G0 functions: drug and immune survival in malignancies like leukemia, immune cell extravasation, tissue regeneration, and development. The goal of our study is to investigate the distinct post-transcriptional mechanisms and gene expression in G0 leukemic cells, to understand G0 roles and persistence in disease. Premise 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 RNAs, 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 reveal signaling changes that modify RNPs in G0 to enable specific gene expression, which allowed targeting of drug resistant G0 in disease (Genome Biol. 2020). Our studies indicate important layers of undiscovered regulation: modification of ribosomes, mRNAs and RNPs and associated non-canonical translation (Science 2020, Nat. Commun. 2020, Science Adv. 2022). Characterization of G0 post-transcriptional changes, will reveal hidden mechanisms that drive G0 survival for disease persistence. 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 survival. Second, modifications on mRNAs, associated RNPs, non-canonical translation factors, translated targets and unique start sites in G0 will be identified to uncover the G0 translatome, expanded at the translation frame. Finally, these will be verified in vivo and in patient samples, to uncover post-transcriptional mechanisms that impact G0 roles and persistence. Impact These studies will uncover new insights into G0 post-transcriptional mechanisms, provide a map of ribosome and RNA modifications, and translation frames, and their impact on G0 roles and survival in disease.