As one of the largest internal organs in the body, liver is very important for metabolism, detoxification and homeostasis. It's reported that liver development is accurately regulated by a gene regulating network consists of FGF, BMP, WNT signal pathways and a lot of transcription factors. However, the functions of microRNA are poorly understood during liver formation. In recent years, it has been reported that mir122 is highly expressed in hepatocytes, and plays a vital role in the metabolic processes of the liver, but its function in liver development remains unclear. In this study, we report that mir122 is specifically expressed in zebrafish (Danio rerio) embryonic liver, and its expression level is notably increased during the differentiation process of hepatoblast into hepatocyte. mir122 inactivation by an antisense morpholino has no influence on the specification, budding and outgrowth of hepatoblast. However, zbrafish hepatoblast can not differentiate into hepatocyte without mir122. Therefore, mir122 is not only involved in liver metabolic functions, but also indispensable for hepatoblast differentiation.%作为机体内最大的脏器之一,肝脏对于机体的新陈代谢、解毒作用以及内环境的稳定有着重要的作用.FGF、BMP 以及WNT 信号通路及众多转录因子形成的基因调节网络精密调控着肝脏的发育,然而小分子RNA在肝脏形成中的功能却所知甚少.近年来的研究发现,mir122 在肝细胞中高表达,对于维持肝脏的代谢功能起着至关重要的作用,但是其在肝脏发育中的功能还不清楚.为了深入探讨mir122 在斑马鱼(Danio rerio)胚胎发育中的作用,文章首先检测了mir122 在发育过程中的时空表达,发现mir122 特异表达在肝脏,并且在肝脏前体细胞向肝细胞分化过程中表达水平显著增高.文章还通过用反义核苷酸Morpholino (MO)敲降mir122 的表达,发现敲降mir122 对肝脏前体细胞的起源、肝原基的形成以及肝脏前体细胞的增殖没有明显的影响,但是,mir122 的缺失导致肝脏前体细胞不能分化为肝细胞.因此,mir122 不仅参与了成体肝脏代谢功能的调节,还在肝脏前体细胞向肝细胞分化过程中不可或缺.
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