Analysis of function of microRNAs in Dlk1-Dio3 region in hematopoietic stem cells

造血干细胞（HSCs，CD 34-KSL）具有自我更新能力和多能性。CD 34-KSL组分中的CD 150+细胞具有长期和骨髓偏向的再增殖活性。我们已经鉴定了对CD 150 + CD 34-KSL组分特异性的microRNA，并将microRNA转导的CD 34-KSL移植到致死辐射的小鼠中。然而，我们无法检测到扩展自我更新活性的microRNA。这部分是由于HSC的异质性，因为已经报道了候选microRNA在巨核细胞中表达。为了评估这一点，我们进行了小鼠骨髓的单细胞移植，其中所有成熟的血细胞都表达荧光蛋白。我们在HSC组分中检测到除了全谱系HSC之外的骨髓限制性再生细胞，这表明一些候选microRNA在谱系定型而不是自我更新中起作用。

Hematopoietic stem cells (HSCs, CD34-KSL) have self-renewal activity and multipotency. CD150+ cells in CD34-KSL fraction have long-term and myeloid-biased repopulating activity. We have identified microRNAs specific to CD150+CD34-KSL fraction and transplanted microRNA-transduced CD34-KSLs into lethally-irradiated mice. However, we could not detect microRNAs that expanded self-renewal activity. This is, in part, due to HSC heterogeneity because candidate microRNAs have been reported to be expressed in megakaryocytes. To assess this, we performed single-cell transplantation of bone marrows from mice in which all mature blood cells express fluorescent protein. We detected myeloid-restricted repopulating cells in addition to full-lineage HSC in HSC fraction, suggesting that some of candidate microRNAs have a role in lineage commitment rather than self-renewal.