摘要
【目的】体外真核表达梅花鹿(Cervus nippon)激活素A重组蛋白并测定其生物活性,为进一步明确激活素A在梅花鹿卵母细胞体外成熟过程中的生理学功能提供基础。【方法】利用RT-PCR技术克隆梅花鹿激活素βA (ActivinβA, ACTBA)亚基基因的cDNA全长序列,同时利用生物信息学对梅花鹿激活素βA的基因特征进行分析。在NCBI数据库下载其他物种激活素βA同源序列,利用Clustalx和MEGA 4软件进行同源比对并构建进化树。构建pcDNA4/ACTBA重组质粒并转染至CHO细胞内,进行目的蛋白的体外表达。采用免疫荧光及Western blot技术对目的蛋白表达情况进行检测,并通过Ni-NTA亲和层析柱对蛋白产物进行纯化。采用Western blot检测了梅花鹿激活素A重组蛋白处理后的猪颗粒细胞中的SMAD2和SMAD3的磷酸化水平。最后采用荧光定量PCR及Western blot检测了梅花鹿激活素A重组蛋白处理后的猪颗粒细胞中类固醇激素合成相关酶的表达量。【结果】克隆得到的梅花鹿ACTBA亚基基因含有1 278 bp的碱基,编码426个氨基酸。同源性比较发现梅花鹿ACTBA基因与牛的ACTBA基因同源性最高达98.4%同源。进化分析表明该基因与同为偶蹄目动物的反刍兽牛和山羊亲缘关系最为接近。经酶切、PCR和测序方法鉴定,成功构建真核表达质粒pcDNA4/ACTBA。免疫荧光显示该质粒在CHO细胞中主要定位在细胞质。Western blot结果显示激活素A的前体蛋白分子量约为58 kD左右。镍亲和层析纯化后的激活素A重组蛋白显著增加SMAD2和SMAD3的磷酸化,表明激活素A可以激活SMAD信号通路。同时成熟的激活素A重组蛋白可以诱导猪颗粒细胞芳香化酶(Aromatase)蛋白表达量上调,类固醇生成急性调节蛋白(steroidogenic acute regulatory protein, StAR)表达量下调,FSH受体基因表达量升高,LH受体基因表达量降低,但胆固醇侧链裂解酶(Cholesterolside-chaincleavageenzyme,CYP11A1orP450scc)及3β-
【Objective】The objective of this study was to investigate the eukaryotic expression and biological activity of recombinant Cervus Nippon Activin A protein, which would provide an experimental basis for further clarification on the physiological function of Activin A in the maturation of the oocytes of Cervus Nippon. 【Method】 The full length cDNA of Activin βA(ACTBA) gene was acquired by RT-PCR(Reverse Transcription-Polymerase Chain Reaction) technology. Bioinformatics tools were used to determine the characteristics of Activin βA sequence. The homologous sequences of Activin βA from other species were downloaded from NCBI, the deduced amino acid sequence of Activin βA was aligned by using the Clustal X(1.83) software, and the phylogenetic tree was constructed by using MEGA 4. Recombinant plasmids of pc DNA4/ACTBA were constructed, and then transfected into CHO cells to express target proteins in vitro. Target proteins were detected by Immunofluorescence technology and Western blot technology, and then purified by Ni-NTA affinity chromatography column. The effects of the treatment of purified Cervus Nippon Activin A on the phosphorylation of SMAD2 and SMAD3 proteins in porcine granulosa cells were investigated through Western blot, as well as the expression levels of steroid hormone-related enzymes in porcine granulosa cells treated with recombinant Cervus Nippon Activin A were detected by real-time PCR and Western blot. 【Result】 The Cervus Nippon Activin A was cloned, which contained 1 278 bp, encoding 426 amino acids. The homology comparison showed that the sequence of ACTBA gene in Cervus Nippon had the highest 98.4% identity with that in cattle. Phylogenetic analysis showed that it had the closest relationship with that in Bos taurus and Capra hircus. The data through endonuclease digestion, PCR and DNA sequencing showed the eukaryotic expression plasmid was constructed successfully. Immunofluorescent results showed that this plasmid expressed in CHO cells successfully, and Activin A protein ma
作者
张宇飞
曹满园
王丽英
赵伟刚
李晓霞
常彤
许保增
ZHANG YuFei;CAO ManYuan;WANG LiYing;ZHAO WeiGang;LI XiaoXia;CHANG Tong;XU BaoZeng(Institute of Special Animal and Plant Sciences,Chinese Academy of Agricultural Sciences/State Key Laboratory for Molecular Biology of Special Economic Animal,Chinese Academy of Agricultural Sciences,Changchun 130112)
出处
《中国农业科学》
CAS
CSCD
北大核心
2020年第5期1058-1070,共13页
Scientia Agricultura Sinica
基金
国家重点研发计划(2018YFC1706601-03)
中国农业科学院创新工程
吉林省国际合作项目(20170414049GH)
中央级公益性科研院所基本科研业务费专项(1610342017025)
关键词
梅花鹿
激活素A
颗粒细胞
真核表达
蛋白纯化
Cervus nippon
Activin A
granulosa cells
eukaryotic expression
protein purification
