中文摘要：

microRNA为短链非编码RNA,通过与靶基因3＇UTR序列互补在转录后水平发挥作用。已有研究表明,microRNA在心脏发育过程中起着重要的调控作用。南极冰鱼因体内缺乏功能性血红细胞,其心脏出现了补偿性增生。前期的研究提示,独角雪冰鱼心脏中特异表达的microRNAs可能与冰鱼心脏的补偿性增生相关。本研究针对南极冰鱼心脏中高表达的miR-210-5p,运用斑马鱼显微注射、靶基因预测等手段研究了miR-210-5p对心脏发育的作用机制。结果表明：斑马鱼胚胎注射miR-210-5p后,出现心包膜水肿,心脏发育畸形等现象。qRT-PCR分析显示,过表达miR-210-5p的斑马鱼胚胎中,心脏发育相关的标志性基因bmp4、smad1、gata6以及tbx2b的表达水平下调。Western blotting分析发现,bmp/smad通路中的BMP2、BMP4、SMAD1、GATA6以及TBX2B的蛋白表达水平也显著下调。通过对tbx20基因3＇UTR的靶基因生物信息学预测,以及对其进行GFP荧光表达分析,发现tbx20基因可能是miR-210-5p的一个靶基因。由此推测,miR-210-5p可能通过抑制tbx20基因的表达,并调控bmp/smad通路以抑制冰鱼心脏发育。

英文摘要：

MicroRNA,a short non-coding RNA chain,plays important roles in post-transcription regulations by targeting gene 3 ＇ UTR through sequence complementary principle. Previous researches showed that microRNAs play important roles in heart development process. Heart development of the Antarctic icefish（ Chionodraco hamatus） shows compensatory physiological enlargements due to the lack of functional red blood cells in the body. Previous studies suggested that microRNAs specifically expressed in the C. hamatus heart may be associated with icefish compensatory physiological enlargement. In this study,according to the highly expressed miR-210-5p,we studied the heart development functional mechanism of miR-210-5p by using zebrafish microinjection and gene＇s target prediction. The results showed that overexpression of miR-210-5p in 72 hdf zebrafish embryos could affect zebrafish heart development,characterized by cardiac malformations such as pericardial edema. QRT-PCR analysis showed that overexpression of miR-210-5p in zebrafish downregulated heart development marker genes including bmp4,smad1,gata6,tbx2 b. Western blot analysis found that the protein expression levels of BMP4,BMP2,SMAD1,GATA6 and TBX2 B were downregulated.According to the bioinformatics prediction and GFP fluorescence analysis,we found tbx20 may be a target of miR-210-5p. Therefore,we speculated that miR-210-5p might inhibit tbx20 gene expression and might suppress heart development of C. hamatus through bmp / smad pathway.