猪bmp15基因报告载体的构建及其特异性

Construction and specificity of porcine bmp15 gene reporter vector

摘要:

为了研究骨形态发生蛋白15 (bmp15) 基因的表达和调控特性，通过克隆猪bmp15基因2.2 kb启动子片段，构建pBMP15-EGFP报告载体，实现监测干细胞向类卵母细胞分化的过程。以猪卵巢组织和中国仓鼠卵巢细胞 (CHO)、成肌细胞 (C2C12)、猪羊水干细胞 (pAFSC) 为材料，通过RT-PCR、免疫荧光、细胞转染、显微注射检测bmp15组织特异性表达，并且通过单层细胞诱导检测该基因体外示踪类卵母细胞获得过程的能力。RT-PCR结果显示bmp15在猪的卵巢组织中特异表达，在CHO中表达，而在C2C12和pAFSC中不表达。卵巢组织切片免疫荧光检测结果显示bmp15表达于卵泡发育的各个阶段。瞬时转染不同细胞发现启动子只在CHO中有活性，而在C2C12和pAFSC中均无活性。显微注射重组质粒片段结果显示增强绿色荧光蛋白 (Enhanced Green Fluorecence Protein，EGFP) 在卵母细胞体外成熟18 h启动表达，并能够持续至4-细胞期胚胎。单层细胞诱导结果显示诱导12 d的pAFSC出现携带EGFP的圆形细胞团。说明bmp15具有表达特异性和示踪干细胞诱导分化为类卵母细胞的潜能。

Abstract:

The aim of this study is to identify the express specificity of bone morphogenetic protein 15 (Bmp15) in porcine. The pBMP15-EGFP reporter vector was constructed from the 2.2 kb fragment of porcine bmp15 promoter to trace the differentiation process of stem cells into oocyte-like cells. We used porcine ovary and Chinese Hamster Ovary cell line (CHO), mouse myoblast cell line (C2C12) and porcine amniotic fluid stem cell (pAFSC) to investigate the expression and regulation of this gene via RT-PCR, immunofluorescence, cell transfection, and microinjection methods. We also used single layer cell differentiation to detect the application potential of bmp15. The results show that bmp15 gene was specifically expressed in the porcine ovary and CHO rather than in C2C12 and pAFSC. In addition, the characteristic of tissue-specific of Bmp15 was detected on CHO instead of other cell lines by transient transfection. We also detected the expression of Bmp15 in oocyte at different development stages by immunofluorescence of fixed paraffin-embedded ovary sections. Furthermore, microinjection results show that bmp15 expressed in oocytes at 18 h of maturation in vitro, and continued up to 4-cell stage embryos. Most importantly, we found that the expression of Bmp15 started at day 12 after inducing pAFSC into oocyte-like cells by transfection; green fluorescent was visible in round cell masses. It indicated that bmp15 has the expression specificity and the pBMP15-EGFP reporter vector can be used to trace Bmp15 action in the differentiation of stem cells into germ cells.