• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Molecular and Cellular Biology >Two distant and precisely positioned domains promote transcription of Xenopus laevis rRNA genes: analysis with linker-scanning mutants.
【24h】

Two distant and precisely positioned domains promote transcription of Xenopus laevis rRNA genes: analysis with linker-scanning mutants.

机译：两个遥远和精确定位的结构域促进Xenopus Laevis RRNA基因的转录：用接头扫描突变体进行分析。

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

To examine the internal organization of the promoter of the Xenopus laevis rRNA gene, we constructed a series of linker-scanning mutants that traverse the rDNA initiation region. The mutant genes, which have 3 to 11 clustered base substitutions set within an otherwise unaltered rDNA promoter sequence, were injected into Xenopus oocyte nuclei, and their transcriptional capacity was assessed by S1 nuclease analysis of the resultant RNA. The data demonstrate that there are two essential promoter domains, the distal boundaries of which coincide with the promoter boundaries established previously by analysis of 5' and 3' deletion mutants. The upstream promoter domain is relatively small and extends from residues ca. -140 to -128. The downstream domain is considerably larger, encompassing residues ca. -36 to +10, and exactly corresponds in both size and position to the mammalian minimal promoter region. The Xenopus rDNA sequence between these two essential domains has a much smaller effect on the level of transcriptional initiation. In light of the fact that a large portion of this intervening region consists of a segment (residues -114 to -72) that is duplicated many times in the upstream spacer to form an rDNA enhancer sequence, it is noteworthy that a "-115/-77 linker scanner," in which virtually this entire segment is replaced by a polylinker sequence, has full promoter activity in the injected Xenopus borealis oocytes. Analysis of a parallel series of spacing change linker-scanning mutants revealed the unexpected result that the relative positions of the upstream and downstream promoter domains are very critical: all spacing alterations of more than 2 base pairs within this 100-base-pair region virtually abolish promoter activity. We conclude that the factors that bind to these two distant promoter domains must interact in a very precise stereospecific manner.
机译：为了检查Xenopus Laevis rRNA基因的促进剂的内部组织，我们构建了一系列遍历RDNA引发区的接头扫描突变体。将3至11种聚类基质取代的突变基因注射到Xenopus卵母细胞核中，并通过S1核酸酶分析评估其转录能力。结果RNA分析。数据表明存在两个基本的启动子结构域，其远端边界与先前通过分析5'和3'缺失突变体确定的启动子界限。上游启动子结构域相对较小并且从残留物延伸。 -140到-128。下游领域的宽大较大，包括残留物。 -36至+10，尺寸和位置恰好对应于哺乳动物最小启动子区域。这两个基本结构域之间的异爪疮序列对转录起始水平的影响大得多。鉴于该介入区域的大部分由在上游垫片中多次复制的区段（残留物-114至-72）组成，以形成RDNA增强子序列，值得注意的是，“-115 / -77连接器扫描仪“其中几乎整个段由粒子序列取代，在注射的外爪蟾卵母细胞中具有完全的启动子活性。平行系列间距改变接头扫描突变体的分析显示出意外结果，上游和下游启动子结构域的相对位置非常关键：这种100个碱基对区域内的所有间距改变超过2个碱基对的几乎废除启动子活动。我们得出结论，结合这两个远处启动子结构域的因素必须以非常精确的立体化方式进行相互作用。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号