Ballagi A E, Ishizaki A, Nehlin J O, Funa K
Ludwig Institute for Cancer Research, Uppsala, Sweden.
Biochem Biophys Res Commun. 1995 May 5;210(1):165-73. doi: 10.1006/bbrc.1995.1642.
The PDGF beta-receptor expression is tightly regulated during embryonic development and in several physiological and pathological situations. To determine the regulatory mechanism of the receptor, a 1.9 kb 5' flanking genomic fragment of the mouse PDGF beta-receptor gene was cloned and analyzed by functional promoter assays. The fragment was shown to exert promoter activity in the luciferase expression vector system in mouse NIH 3T3 fibroblast and NB41 neuroblastoma cell lines as well as rat ST15A cerebellar cell lines. Functional studies on deletion mutants revealed several putative regulatory sequences. The deletion mutants acted similarly in NB41 cells and in ST15A cells, both of neuronal origin, but differently in the NIH 3T3 fibroblasts. No TATA box was found in the analyzed promoter region, however, site directed mutagenesis of a CCAAT motif, located 60 basepair upstream of the transcriptional start site, almost completely abolished the promoter activity in all cell types.
血小板衍生生长因子β受体（PDGF β受体）的表达在胚胎发育过程以及多种生理和病理情况下受到严格调控。为确定该受体的调控机制，克隆了小鼠PDGF β受体基因1.9 kb的5'侧翼基因组片段，并通过功能启动子分析进行研究。该片段在小鼠NIH 3T3成纤维细胞、NB41神经母细胞瘤细胞系以及大鼠ST15A小脑细胞系的荧光素酶表达载体系统中表现出启动子活性。对缺失突变体的功能研究揭示了几个假定的调控序列。缺失突变体在NB41细胞和ST15A细胞（均源自神经组织）中的作用相似，但在NIH 3T3成纤维细胞中的作用不同。在所分析的启动子区域未发现TATA框，然而，对位于转录起始位点上游60个碱基对处的CCAAT基序进行定点诱变，几乎完全消除了所有细胞类型中的启动子活性。
