Jin W, Huang E S, Bi W, Cote G J
Section of Endocrinology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
J Biol Chem. 1998 Jun 26;273(26):16170-6. doi: 10.1074/jbc.273.26.16170.
Alternative RNA processing of the human fibroblast growth factor receptor-1 transcript results in receptor forms that vary in their affinity for fibroblast growth factor. An alternative RNA processing event involving recognition of the alpha-exon is deregulated during neoplastic transformation of glial cells. We have previously established a splicing reporter/transfection cell culture model system to identify sequences involved in recognition of this exon. In this study, the system was used to identify two sequence elements that differentially function to regulate splicing of this exon. Exclusion of the alpha-exon in glioblastoma cells specifically required the downstream intron sequence comprising the 5'-splice site. Replacement or mutation of this sequence increasing complementarity to U1 RNA resulted in enhanced exon recognition in SNB-19 glioblastoma cells. Sequences within the exon were found to be required for alpha-exon inclusion. Deletion and gain-of-function experiments identified a 69-nucleotide exon sequence that was specifically required for alpha-exon inclusion. These studies indicate that multiple sequences are required for the regulated recognition of the alpha-exon.
人类成纤维细胞生长因子受体-1转录本的可变RNA加工产生了对成纤维细胞生长因子亲和力不同的受体形式。在胶质细胞的肿瘤转化过程中，涉及α外显子识别的一种可变RNA加工事件失调。我们之前建立了一个剪接报告基因/转染细胞培养模型系统，以鉴定参与该外显子识别的序列。在本研究中，该系统被用于鉴定两个对调节该外显子剪接起不同作用的序列元件。胶质母细胞瘤细胞中α外显子的排除特别需要包含5'-剪接位点的下游内含子序列。该序列的替换或突变增加了与U1 RNA的互补性，导致SNB-19胶质母细胞瘤细胞中外显子识别增强。发现外显子内的序列是α外显子包含所必需的。缺失和功能获得实验确定了一个69个核苷酸的外显子序列，它是α外显子包含所特别需要的。这些研究表明，α外显子的调控识别需要多个序列。
