MULTIPLE PROCESSING-DEFECTIVE MUTATIONS IN A MAMMALIAN HISTONE PRE-MESSENGER-RNA ARE SUPPRESSED BY COMPENSATORY CHANGES IN U7 RNA BOTH INVIVO AND INVITRO
MULTIPLE PROCESSING-DEFECTIVE MUTATIONS IN A MAMMALIAN HISTONE PRE-MESSENGER-RNA ARE SUPPRESSED BY COMPENSATORY CHANGES IN U7 RNA BOTH INVIVO AND INVITRO
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DOI：
10.1101/gad.5.9.1709
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发表时间：
1991-09-01
影响因子：
10.5
通讯作者：
STEITZ, JA
中科院分区：
文献类型：
--
作者：
BOND, UM;YARIO, TA;STEITZ, JA
为了研究哺乳动物U 7 snRNA和高度可变的组蛋白下游元件（HDE）之间的碱基配对在哺乳动物组蛋白前体mRNA的3 '端成熟过程中的作用，我们突变了小鼠H2 A-614基因的HDE，并在体内和体外测定了HeLa细胞中的加工。HDE中的9个核苷酸缺失或嘧啶取代6个嘌呤的封闭取代消除了所有3 '端加工。将补偿性变化引入合成的人U 7基因，其转录物在体内组装成Sm snRNP。在体内通过共表达相应的U 7抑制RNA和在体外通过使用从含有U 7抑制基因的HeLa细胞制备的核提取物获得了对HDE内的6-嘌呤取代以及3-嘌呤取代的抑制。我们的研究结果不仅为哺乳动物组蛋白前体mRNA的U 7 snRNP和HDE之间的碱基配对提供了遗传证据，而且揭示了对碱基配对区域性质的剧烈变化的意外耐受性。
To study the role of base-pairing between the mammalian U7 snRNA and the highly variable histone downstream element (HDE) during the 3'-end maturation of mammalian histone pre-mRNAs, we mutated the HDE of the mouse H2A-614 gene and assayed processing in HeLa cells both in vivo and in vitro. Either a 9-nucleotide deletion or a block substitution of pyrimidines for 6 purines within the HDE abolished all 3'-end processing. Compensatory changes were introduced into a synthetic human U7 gene, whose transcripts assemble into Sm snRNPs in vivo. Suppression of the 6-purine substitution as well as a 3-purine substitution within the HDE was obtained in vivo by coexpressing the corresponding U7 suppressor RNAs and in vitro by using nuclear extracts prepared from HeLa cells containing U7 suppressor genes. Our results not only provide genetic evidence for base-pairing between the U7 snRNP and the HDE of mammalian histone pre-mRNAs but reveal an unexpected tolerance to drastic changes in the nature of the base-paired region.