The first exon of the c‐myc proto‐oncogene contains a novel positive control element.
The first exon of the c‐myc proto‐oncogene contains a novel positive control element.
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c-myc 原癌基因的第一个外显子包含一个新的阳性对照元件。
DOI：
10.1002/j.1460-2075.1986.tb04682.x
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
K. Marcu
中科院分区：
文献类型：
--
作者：
J. Yang;E. Remmers;K. Marcu
我们已经在该基因转录起始点P1和P2下游的c-myc第一外显子中发现了一个正调控因子。我们将myc-CAT(氯霉素乙酰转移酶)杂合基因导入三个细胞系(BJAB、COS和HeLa)，并通过CAT酶活性、S1核酸酶保护和核‘连续’转录实验检测它们的表达。第一外显子3‘端46bp的缺失会导致myc-CAT表达和P2活性下降。缺少正常myc启动子的一个438bp的外显子1片段有效地驱动了SV40早期启动子的表达。我们发现，这第一个外显子片段只有在其附近启动子的3‘端有意义的方向上才能有效地发挥正调控作用。Myc第一外显子和SV40增强子的积极作用是互补的。
We have identified a positive modulator within the c‐myc first exon downstream of the gene's transcription initiation sites, P1 and P2. We introduced myc‐CAT (chloramphenicol acetyltransferase) hybrid genes into three cell lines (BJAB, COS and HeLa) and measured their expression by either CAT enzymatic activity, S1 nuclease protection or by a nuclear ‘run‐on’ transcription assay. Removal of 46 bp from the 3′ end of the first exon results in a decrease of myc‐CAT expression and P2 activity. A 438‐bp exon 1 segment, lacking the normal myc promoters, efficiently drives the expression of SV40 early promoters. We find that this first exon segment efficiently functions as a positive modulator only in its sense orientation, 3′ of a nearby promoter. The positive effects of the myc first exon and the SV40 enhancer are complementary.