中文摘要：

微小RNA（microRNA,miRNA）是一类在进化上高度保守、长度约20～24 nt的小分子非编码RNA,能通过与靶基因3′非翻译区相结合从而抑制靶基因的翻译或降解靶基因。let-7 microRNA是发现较早的一类miRNA,最早在线虫中发现能调控细胞分裂的时序。此后大量证据表明,let-7参与动物多个器官发育的调控过程,并与人类疾病发生密切相关。该文综述了近年来let-7调控动物脑、神经及心肺系统等器官发育的研究成果,初步阐述了let-7调控动物器官发育可能的作用机制,以期为深入研究let-7的功能奠定基础。

英文摘要：

MicroRNAs（miRNAs） are a class of small non-coding RNAs,about 20～24 nucleotides in length.They can inhibit target genes translation or degrade them directly through combination with the complementary sequences in the 3′-UTRs of target mRNAs.The let-7 miRNAs were originally found in the nematode Caenorhabditis elegans,where they mainly regulated the timing of cell division.Increasing evidences indicate that let-7 miRNAs are associated with animal organs development and human diseases.This review summarized the recent progresses about the function of let-7 miRNAs in the development of brain,neuron,lung and cardiovascular system.Meanwhile,we elucidated the possible mechanism of let-7 miRNAs regulating the developmental processes of animal organs that might provide the basis for further illustrating the function of let-7 miRNAs.