DUPLICATED CARG BOX DOMAINS HAVE POSITIVE AND MUTUALLY DEPENDENT REGULATORY ROLES IN EXPRESSION OF THE HUMAN ALPHA-CARDIAC ACTIN GENE
DUPLICATED CARG BOX DOMAINS HAVE POSITIVE AND MUTUALLY DEPENDENT REGULATORY ROLES IN EXPRESSION OF THE HUMAN ALPHA-CARDIAC ACTIN GENE
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DOI：
10.1128/mcb.7.8.2803
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发表时间：
1987-08-01
影响因子：
5.3
通讯作者：
KEDES, L
中科院分区：
文献类型：
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作者：
MIWA, T;KEDES, L
从转录起始位点到-177碱基对（bp）的上游区域。心脏肌动蛋白基因仅在肌肉细胞中指导细菌氯霉素乙酰转移酶（CAT）基因的瞬时表达（a . Minty and L. Kedes, Mol. Cell.）。《圣经》6:25 -2136,1986)。我们通过额外的5”缺失、连接扫描突变和插入缺失突变来修饰该启动子区域，并证明位于-140和-100 bp的两个CArG[对于CC(A+T rich)6GG]基序内和邻近的不对称序列在转录中起着重要的积极作用。伴随一个CArG盒区破坏的转录活性的显著损伤可以通过任何一种方式恢复。这表明这两个元素以相互依赖和相似的方式相互作用。此外，包含CArG盒子的DNA片段对由。alpha引导的转录具有显著的竞争活性。-心脏肌动蛋白启动子在体内竞争试验。我们得出结论，每个CArG盒周围的两个序列可能与同一类反式作用阳性因子相互作用，并且这些相互作用可能介导肌肉特异性表达。两个CArG区域中的每一个似乎都被这样一个正因子独立地结合，并且这些区域以协同方式支持高水平转录。该调控区域的转录活性与其与TATA盒的距离（-30 bp）成正比，并且严格依赖于转录方向。因此，这个上游区域不是一个增强子，而是一个组织特异性的上游调控元件。
An upstream region from the transcription initiation site to -177 base pairs (bp) of the human .alpha.-cardiac actin gene directs the transient expression of a bacterial chloramphenicol acetyltransferase (CAT) gene only in muscle cells (A. Minty and L. Kedes, Mol. Cell. Biol. 6:2125-2136, 1986). We modified this promoter region by additional 5'' deletions, linker-scanning mutations, and insertion-deletion mutations and demonstrated that the asymmetrical sequences in and adjacent to two CArG [for CC(A+T rich)6GG] motifs, located at -140 and -100 bp, play an important positive role in transcription. The significant impairment of transcriptional activity that accompanies the disruption of one CArG box region can be restored by either. This demonstrated that these two elements interact in a mutually dependent and similar manner. Furthermore, a DNA fragment that includes the CArG boxes had significant competitive activity for transcription directed by the .alpha.-cardiac actin promoter in an in vivo competition assay. We conclude that the two sequences around each CArG box may interact with the same class of trans-acting positive factor(s) and that these interactions may mediate muscle-specific expression. Each of the two CArG regions appears to be bound independently by such a positive factor(s), and the regions support high-level transcription in a synergistic manner. The transcriptional activity of this regulatory region is proportional to its distance from a TATA box (at -30 bp) and is strictly orientation dependent relative to the direction of transcription. Therefore this upstream region is not an enhancer but is a tissue-specific regulatory upstream element.