尿素转运因子B（Urea transporters B, UT-B)在牛瘤胃尿素氮转运中起关键作用，GATA2转录因子参与机体氮周转与利用的启动调控。前期研究发现GATA2转录因子对UT-B启动子具有调控作用，但其机制不清楚。本项目首先构建UT-B基因的启动子载体与GATA2蛋白真核表达载体，共转染奶牛瘤胃上皮细胞，通过荧光素酶报告基因研究GATA2蛋白过表达对UT-B启动子转录活性的调控作用，抗体超迁移试验确证GATA2与UT-B启动子位点的特异结合；丁酸作用下，Western-blotting检测膜结合的前体GATA2蛋白和核内成熟GATA2蛋白的含量变化，以探讨GATA2调控UT-B基因启动子的作用机制；动物试验探明丁酸通过GATA2调控UT-B表达的效应。对探明奶牛瘤胃氮再循环机制，丰富牛氮素营养理论具有重要意义。

Urea transporters B (UT-B) may play a critical role in the ruminal urea-N transport in cow. GATA2 transcription factor mediates nitrogen turnover and utilization in the organism. Previous research has found the regulation function of GATA2 transcription factor on UT-B promoters, however, the machanism still was not clear. In this study, UT-B promoter vector and eukaryotic expression vector were constracted and co-transfected into the ruminal epithelium cell of the cow. The effect of GATA2 overexpression on the transcriptional activity of the UT-B promoter was analysed through the firefly luciferase activities. The binding site was further confirmed by gel shift assay and super gel shift assay. The abundance of nuclear and membrane GATA2 was analysed by Western-blotting in the presence of butyrate. The regulation machanism of GATA2 transcription factor on UT-B promoters was explored.The effect of butyric acid regulating UT-B promoter transcription through GATA2 was researched by animal study. It was of important significance to expound the ruminal nitrogen recycle transport in dairy cow, and to enrich nitrogen nutrition theory in cow.