Control of human hemoglobin switching by LIN28B-mediated regulation of BCL11A translation (Ribo-seq, RNA-seq)

While BCL11A protein is not well synthesized at these earlier stages of development, its mRNA curiously continues to be associated with ribosomes. Through unbiased proteomic analyses in erythroid cells, we demonstrate that the RNA-binding protein LIN28B, which is developmentally expressed in a reciprocal pattern to BCL11A, directly interacts with ribosomes. We show that the observed suppression of BCL11A protein translation is mediated by LIN28B through a direct interaction with BCL11A mRNA and independent of its role in let-7 microRNA biogenesis. Finally, we show that BCL11A is the major functional target in LIN28B-mediated fetal hemoglobin induction. Our results reveal a previously unappreciated regulatory mechanism underlying human hemoglobin switching and illuminate opportunities for developing improved treatments for sickle cell disease and Beta-thalassemia Overall design: Four replicates of ribosome profiling in adult and newborn erythroid cells with matching RNA-seq per sample.

尽管在发育早期阶段，BCL11A蛋白的合成水平极低，但令人费解的是，其mRNA仍持续与核糖体结合。通过在红细胞系细胞中开展无偏蛋白质组学分析，我们证实RNA结合蛋白（RNA-binding protein）LIN28B的发育表达模式与BCL11A呈反比，且该蛋白可直接与核糖体相互作用。我们发现，所观察到的BCL11A蛋白翻译抑制过程由LIN28B介导，其机制为LIN28B直接结合BCL11A mRNA，且不依赖其在let-7微RNA（microRNA）生物发生中的功能。最后，我们证实BCL11A是LIN28B介导的胎儿血红蛋白（fetal hemoglobin）诱导过程中的主要功能性靶标。本研究结果揭示了此前未被认知的人类血红蛋白转换调控机制，同时为开发镰状细胞病（sickle cell disease）与β-地中海贫血（Beta-thalassemia）的优化治疗方案指明了新方向。实验整体设计：对成人及新生儿红细胞系细胞进行核糖体谱分析（ribosome profiling），每组设置4个生物学重复，每个样本同步配套RNA测序（RNA-seq）。