Role of microRNAs in T cell development

microRNA 在 T 细胞发育中的作用

• 批准号: 10702475
• 负责人: Alfred Singer
• 金额: $ 38.68万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10702475
• 关键词: Apoptosis; Apoptotic; Cells; Development; Dicer Enzyme; Equilibrium; Eukaryota; Family; Gene Expression; Generations; Genes; Goals; Messenger RNA; MicroRNAs; Mus; Post-Transcriptional Regulation; Protein Biosynthesis; RNA; RNA Interference; Role; T-Cell Development; T-Lymphocyte; Thymocyte Development; Thymus Gland; Untranslated RNA; ZNF145 gene; conditional knockout; protein expression; thymocyte; transcription factor

RNA intererence is a one of the major mechanisms of post-transcriptional regulation of protein expression in eukaryotes. This mechanism is using small non-coding RNAs (miRNAs) to destabilize specific mRNAs and to suppress protein synthesis. Many miRNAs genes are expressed in T cells during development in a thymus. However the function of RNAi in T cell development remains unclear. To investigate the role of RNAi during thymic development we generated conditional knockout of the enzyme Dicer in the mouse, which is critical for miRNA generation. We observed a dramatic reduction in the number of thymocytes in Dicer-deficient mice and we determined that the reason is a block of progression from DN to DP stage during thymocyte development. Importantly, we found an alteration in the balance between pro- and anti-apoptotic factors in RNAi deficient DP thymocytes. We also observed that RNAi-deficient thymocytes are rapidly undergoing apoptosis. Most importantly, we have also identified the precise gene whose expression is downregulated by microRNAs to permit survival of developing T cells in the thymus. Because the Let7 family of microRNAs is the largest miRNA family, we have now examined the role of Let7 family microRNAs in T cell development in the thymus. We found that Let7 miRNAs target the transcription factor PLZF and so regulate the differentiation of innate-like T cells (i.e. NKT cells) in the thymus.

RNA干扰是真核生物中蛋白质表达转录后调控的主要机制之一。该机制利用小非编码 RNA (miRNA) 来破坏特定 mRNA 的稳定性并抑制蛋白质合成。许多 miRNA 基因在胸腺发育期间的 T 细胞中表达。然而RNAi在T细胞发育中的功能仍不清楚。为了研究 RNAi 在胸腺发育过程中的作用，我们在小鼠体内条件性敲除 Dicer 酶，这对于 miRNA 的生成至关重要。 我们观察到 Dicer 缺陷小鼠的胸腺细胞数量急剧减少，我们确定其原因是胸腺细胞发育过程中从 DN 阶段到 DP 阶段的进展受阻。重要的是，我们发现 RNAi 缺陷的 DP 胸腺细胞中促凋亡因子和抗凋亡因子之间的平衡发生了变化。我们还观察到 RNAi 缺陷的胸腺细胞正在迅速凋亡。最重要的是，我们还鉴定了一种精确的基因，其表达可被 microRNA 下调，从而使胸腺中发育中的 T 细胞能够存活。由于 Let7 家族的 microRNA 是最大的 miRNA 家族，因此我们现在研究了 Let7 家族 microRNA 在胸腺 T 细胞发育中的作用。我们发现 Let7 miRNA 靶向转录因子 PLZF，从而调节胸腺中先天性 T 细胞（即 NKT 细胞）的分化。