融合启动子调控下的t-PA cDNA乳腺定位表达

Fused promoter regulating t-PA cDNA expression in mammary gland

由牛 β- Casein启动子与大鼠 WAP启动子融合构建了 t- PA c DNA乳腺定位表达载体 p SVL-β△ WAP- PA,以研究 t- PA乳腺定位表达的调控。结果表明 ,将表达载体 p SVL- βb- PA,p SVL- WAP- PA及 p SVL-β△ WAP- PA分别直接注入怀孕的家兔乳腺管中 ,溶圈试验显示 3种表达载体均能在家兔乳腺中表达 ,且以分娩后第 4天的乳汁中表达水平最高 ,分别为 390 ,430和 6 70 ng/ m L。证明 0 .6 kb的牛 β- Casein上游调控序列具有一定的定位表达调控能力。融合启动子较单纯的 β- Casein或 WAP启动子调控下的 t- PA c

In order to study the expressing regulation of t PA cDNA in mammary gland,two specific expression plasmids,pSVL β b PA and pSVL β △WAP PA,containing t PA cDNA gene,were constructed by fusing with bovine β Casein promoter,respectively.The three plasmids,pSVL β b PA?pSVL WAP PA and pSVL β △WAP PA were mixed with liposome and injected directly into pregnant rabbit mammary gland duct.Fibrin clot lysis assay showed that the three plasmids could express t PA in rabbit milk.The expression level was 390,430 and 670 ng/mL on day 4,respectively.It occured that 0.6 kb bovine 5regulatory region of β Casein gene was able to direct low level expression of t PA cDNA in mammary gland,and the expression level of t PA cDNA regulated by fused promoter was higher than β Casein or WAP promoter.It also provides the useful information for studing the regulation of specific expression in mammary gland and the establishment of t PA mammary gland bioreactor.