中文摘要：

SET和MYND结构域蛋白3（SET and MYND domain-containing protein 3,SMYD3）是一种组蛋白H3赖氨酸残基4（Lysine 4,K4）三甲基化转移酶（H3K4 trimethyltransferase）,其在多种癌细胞中高表达,能够促进癌细胞增殖、迁移和侵袭。为研究SMYD3在牛胎儿成纤维细胞（bovine embryonic fibroblast cells,b EFs）中的作用,以牛（Bos taurus）c DNA为模板,PCR扩增牛SMYD3基因CDS,并将其连接到巨细胞病毒（Cytomegalovirus,CMV）启动子表达载体p IRES2-Zsgreen1上,构建高表达SMYD3基因载体p SMYD3-IRES2-Zsgreen1。表达载体转染b EFs后,q RT-PCR和Western blot检测其表达,噻唑蓝（3-（4,5）-dimethylthiahiazo（-z-y1）-3,5-di-phenytetrazoliumromide,MTT）比色法监测其对细胞生长的影响。用鼠（Mus musculus）源POU5f1转录因子（octamer-binding transcription factor 4,Oct4）、性别决定基因相关转录因子2（SRY（sex determining region Y）-box 2,Sox2）、鸟类骨髓细胞瘤元癌基因同源基因（avian myelocytomatosis viral oncogene homolog,c-Myc）和Kruppel样因子4（Kruppel-like factor 4,Klf4）诱导高表达SMYD3基因的b EFs,研究SMYD3对b EFs诱导效率的影响。酶切鉴定结果表明,表达载体p SMYD3-IRES2-Zsgreen1构建成功;q RT-PCR和Western blot结果显示,SMYD3能够在b EFs正常表达,通过荧光筛选得到了稳定表达SMYD3基因的b EFs p SMYD3。MTT结果显示,SMYD3能够促进b EFs的生长;转录因子诱导p SMYD3细胞后,与对照组相比,细胞克隆形成率明显提高,且克隆均为OCT4、NANOG同源框（nanong homeobox,NANOG）和SOX2染色阳性,说明SMYD3能够促进诱导性多能干细胞（induced pluripotent stem cells,i PSCs）诱导效率。本研究表明SMYD3对b EFs的生长有促进作用,并且能够提高b EFs向i PSCs的诱导效率,为牛诱导干细胞制备及机理研究提供新的思路。

英文摘要：

SET and MYND domain-containing protein 3（SMYD3） is a histone H3 Lysine 4trimethyltransferase,which overexpresses in many cancers and can promote cells proliferation,migration and invasion.In order to study the function of SMYD3 in bovine embryonic fibroblast cells（b EFs）,SMYD3 CDS was obtained from bovine（Bos taurus） and inserted into the vector p IRES2-Zsgreen1 to construct overexpression vector p SMYD3-IRES2-Zsgreen1.p SMYD3-IRES2-Zsgreen1 was transfected into b EFs and q RT-PCR and Western blot were used to verify its expression.Also,the cell growth was recorded by detecting the absorbancy of 3-（4,5）-dimethylthiahiazo（-z-y1）-3,5-di-phenytetrazoliumromide（MTT） every 24 h for 7 d.At last,the transgenic b EFs were infected with lentiviral vectors expressing the mouse（Mus musculus）octamer-binding transcription factor 4（Oct4）,SRY（sex determining region Y）-box 2（Sox2）,avian myelocytomatosis viral oncogene homolog（c-Myc） and Kruppel-like factor 4（Klf4） transcription factors,respectively,to obtain the bovine induced pluripotent stem cells（i PSCs）.The enzyme digestion results showed that the vector p SMYD3-IRES2-Zsgreen1 was correctly constructed.The q RT-PCR and Western blot results indicated that SMYD3 overexpressed in p SMYD3-IRES2-Zsgreen1 transfected b EFs,which cells growth improved comparing with the control vector transgenic cells.After induction by the 4 transcription factors,the SMYD3 transgenic cells formed more stem cell-like clones,which displayed OCT4,NANOG homeobox（NANOG） and SOX2 immunofluorescence staining positively.These results established and firstly reported that SMYD3 could promote b EFs growth and induction efficiency for i PSCs,which provides basic data for the strategies of preparing bovine i PSCs and improves understanding of the molecular basis of i PSCs.