To construct mammal expression plasmid pcDNA 3.1 ( + )/GDF-5 and check the expression of it in bone marrow mesenchyal stem cells of mice.

• 目的:通过基因重组技术体外构建真核表达质粒pcDNA3.；1(+)/GDF-5；并检测其在小鼠骨髓基质干细胞中的表达。