COOPERATION BETWEEN CCAAT AND OCTAMER MOTIFS IN THE DISTAL SEQUENCE ELEMENT OF THE RAT U3 SMALL NUCLEOLAR RNA PROMOTER
COOPERATION BETWEEN CCAAT AND OCTAMER MOTIFS IN THE DISTAL SEQUENCE ELEMENT OF THE RAT U3 SMALL NUCLEOLAR RNA PROMOTER
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DOI：
10.1093/nar/19.15.4209
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发表时间：
1991-08-11
影响因子：
14.9
通讯作者：
WEINER, AM
中科院分区：
文献类型：
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作者：
ACH, RA;WEINER, AM
哺乳动物U3小核仁RNA启动子具有高度保守的远端序列元件（DSE），其由CCAAT和由11-12个碱基对分开的八聚体基序组成。在这里，我们表明，这两个图案都需要在非洲爪蟾卵母细胞中的大鼠U3D基因的转录。CCAAT基序的缺失留下残留的DSE活性，而八聚体基序的去除则没有。改变两个基序之间的保守间距通常抑制转录小于删除任一基序，但增加基序之间的间距一个螺旋圈的DNA保留正常水平的转录。我们还表明，大鼠U3D DSE功能等同于人U2 snRNA DSE，它由相邻的GC和八聚体基序组成，并且来自单纯疱疹病毒胸苷激酶启动子的元素可以取代部分或全部的U3D DSE。这些数据显然是自相矛盾的;尽管高度进化保守，U3 DSE对突变相对不敏感，其他上游基序也能够驱动U3基础启动子的转录。我们认为U3 DSE的保守结构可能是调节U3转录所需的，而不是U3转录的效率。
Mammalian U3 small nucleolar RNA promoters possess a highly conserved distal sequence element (DSE) consisting of CCAAT and octamer motifs separated by 11-12 base pairs. We show here that both motifs are required for transcription of a rat U3D gene in Xenopus oocytes. Deletion of the CCAAT motif leaves residual DSE activity, while removal of the octamer motif does not. Changing the conserved spacing between the two motifs generally inhibits transcription less than deletion of either motif, but increasing the spacing between the motifs by one helical turn of DNA preserves normal levels of transcription. We also show that the rat U3D DSE is functionally equivalent to the human U2 snRNA DSE, which consists of adjacent GC and octamer motifs, and that elements from the Herpes Simplex Virus thymidine kinase promoter can replace part or all of the U3D DSE. These data are apparently paradoxical; despite high evolutionary conservation, the U3 DSE is relatively insensitive to mutation, and other upstream motifs are also able to drive transcription from the U3 basal promoter. We suggest that the conserved structure of the U3 DSE may be required for regulation rather than efficiency of U3 transcription.