CHARACTERIZATION OF THE MOUSE TRANSFORMING GROWTH FACTOR-BETA-1 PROMOTER AND ACTIVATION BY THE HA-RAS ONCOGENE
CHARACTERIZATION OF THE MOUSE TRANSFORMING GROWTH FACTOR-BETA-1 PROMOTER AND ACTIVATION BY THE HA-RAS ONCOGENE
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DOI：
10.1128/mcb.11.1.84
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发表时间：
1991-01-01
影响因子：
5.3
通讯作者：
SPORN, MB
中科院分区：
文献类型：
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作者：
GEISER, AG;KIM, SJ;SPORN, MB
我们克隆并测序了小鼠基因组转化生长因子 β-1 (TGF-β-1) DNA 片段，其中包括该基因的 5' 非翻译区和调控区。 与人类 TGF-β-1 基因的高序列同源性（翻译起始位点上游 2.7 kb DNA 中的核苷酸一致性为 66%）表明 TGF-β-1 转录调控的进化保守性。 注意到启动子区域不存在 TATA 或 CAAT 盒序列，但存在多个 Sp1 结合和 AP-2 样序列，正如之前报道的人类基因一样。 通过 S1 核酸酶分析鉴定出两个相距 290 bp 的转录起始位点；这些对应于具有866和576个核苷酸的5'非翻译前导序列的转录物。 对不同小鼠组织的 S1 分析表明，尽管 TGF-β-1 mRNA 转录物的总水平在组织之间存在差异，但两种转录物以相同的比例存在。 通过使用在小鼠 AKR-2B 成纤维细胞中测定的氯霉素乙酰转移酶融合基因，证明了两个转录起始位点附近的启动子活性。 还证明了 Ha-ras 癌基因对启动子的转录激活。 最小启动子构建体（第一和第二转录起始位点的 5' 分别为 113 和 104 bp）足以用于 Ha-ras 的诱导。这些研究表征了小鼠 TGF-β-1 基因的 5' 结构和基础启动子活性，以及 Ha-ras 癌基因对 TGF-β-1 的转录激活作用。
We have cloned and sequenced a mouse genomic transforming growth factor beta-1 (TGF-beta-1) DNA fragment that includes the 5' untranslated and regulatory regions of the gene. High-sequence homology with the human TGF-beta-1 gene (66% nucleotide identity in 2.7 kb of DNA upstream of the translational start site) suggested evolutionary conservation of transcriptional regulation for TGF-beta-1. The absence of TATA or CAAT box sequences but the presence of several Sp1-binding and AP-2-like sequences in the promoter region was noted, as previously reported for the human gene. Two transcriptional initiation sites separated by 290 bp were identified by S1 nuclease analysis; these corresponded to transcripts with 866 and 576 nucleotides of 5' untranslated leader sequence. S1 analysis of different mouse tissues indicated that the two transcripts were present in the same ratio even through the total level of TGF-beta-1 mRNA transcripts varied between tissues. Promoter activity adjacent to both transcriptional start sites was demonstrated by using chloramphenicol acetyltransferase fusion genes assayed in mouse AKR-2B fibroblast cells. Transcriptional activation of the promoter by the Ha-ras oncogene was also demonstrated. The minimal promoter constructs (113 and 104 bp 5' of the first and second transcriptional start sites, respectively) were sufficient for induction by Ha-ras. These studies characterize the 5' structure and basal promoter activity of the mouse TGF-beta-1 gene as well as the transcriptional activation of TGF-beta-1 by the Ha-ras oncogene.