Immunity in a naïve organism is tightly controlled. Adequate proportions of the many immune cell subsets must be produced to mount efficient responses to eventual challenges. In addition, a functioning immune system is highly dynamic at steady state. Mature immune cells must be positioned properly and/or circulate to facilitate the detection of dangers. They must also be poised to promptly react to unusual encounters, while ignoring innocuous germs and self. Numerous regulatory mechanisms act at the molecular level to generate such an exquisite structure, including miRNA-mediated repression of protein synthesis. Notably, the miRNAs from the miR-142 locus are preferentially expressed in hematopoietic cells. Their importance is underscored by the deeply disturbed immune system seen upon inactivation of the locus in mice. In this review, we explore reported roles for the miR-142 miRNAs in the shaping of immunity in vertebrates, discussing in particular their contributions to the generation, migration and survival of hematopoietic cells.

幼稚有机体的免疫力是受到严格控制的。必须产生足够比例的许多免疫细胞亚群，才能对最终的挑战做出有效的反应。此外，功能正常的免疫系统在稳定状态下是高度动态的。成熟的免疫细胞必须正确定位和/或循环以促进危险的检测。他们还必须做好准备，对不寻常的遭遇做出迅速反应，同时忽略无害的细菌和自身。许多调控机制在分子水平上发挥作用，产生如此精致的结构，包括 miRNA 介导的蛋白质合成抑制。值得注意的是，来自 miR-142 位点的 miRNA 优先在造血细胞中表达。小鼠基因座失活后免疫系统受到严重干扰，这凸显了它们的重要性。在这篇综述中，我们探讨了 miR-142 miRNA 在脊椎动物免疫形成中的作用，特别讨论了它们对造血细胞的生成、迁移和存活的贡献。