Functions of the Abundant U-snRNPs
Functions of the Abundant U-snRNPs
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丰富的 U-snRNP 的功能
DOI：
10.1007/978-3-642-73020-7_5
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发表时间：
1988
影响因子：
3.7
通讯作者：
W. Keller
中科院分区：
文献类型：
--
作者：
J. Steitz;D. Black;V. Gerke;K. A. Parker;A. Krämer;D. Frendewey;W. Keller
在这一章中，实验进行了审查，导致从最初的假设U1 snRNP在前mRNA剪接的作用，以阐明所有丰富的核质snRNP（U1，U2，U4/6，和U 5）在高等真核生物中的功能。正如其他人所讨论的（Lustig等，1986; Padgett等，1986;绿色，1986; Maniatis和Reed，1987; Sharp，1987），从初级转录物合成到剪接产物的过程可以分为不同的步骤：必须存在一种机制，通过这种机制，远处的剪接位点被识别、接近并精确对齐。这是导致内含子切除和外显子连接的实际化学切割-连接反应的先决条件。在自剪接RNA的情况下，识别比对通过特异性分子内碱基配对相互作用（顺式比对）完成，切割连接由位于内含子内的催化RNA序列介导（由Cech和Bass 1986综述）。相反，在体外研究中，核前体mRNA的剪接需要大量的反式作用成分.通过snRNP与保守的前mRNA序列的特异性结合进行识别。U1 snRNP与5'剪接位点相互作用，U2 snRNP与分支位点相互作用，而U 5 snRNP最可能与3'剪接位点相互作用。有令人信服的证据表明，U1 snRNP的识别模式是通过U1 snRNA 5'端序列与pre-mRNAs 5'剪接位点序列之间的分子间碱基配对进行的。同样，它已被证明在S。在酿酒酵母中，其U2类似物（LSR 1或snR 20）通过与内部snRNA序列的碱基配对识别保守的分支点共有序列。相反，U 5 snRNP的结合似乎是由一种特异性蛋白介导的，该蛋白能够识别位于3'剪接位点上游的聚嘧啶段。U4/U6颗粒虽然参与剪接，但可能不直接与前体mRNA结合，而是与其他snRNP相互作用，将剪接复合物折叠成特定的空间构型，从而导致剪接位点的精确对齐。主要的U-snRNP与前体mRNA的有序和顺序结合由额外的蛋白质因子介导，并导致称为剪接体的大的多组分复合物的逐步组装，其形成可以通过在速度梯度中沉降或通过在非变性丙烯酰胺凝胶中电泳来研究。
In this chapter experiments are reviewed which led from the initial hypothesis about the role of U1 snRNP in pre-mRNA splicing to the elucidation of the function of all abundant nucleoplasmic snRNPs (Ul, U2, U4/6, and U5) in higher eukaryotes. As discussed also by others (Lustig et al. 1986; Padgett et al. 1986; Green 1986; Maniatis and Reed 1987; Sharp 1987), the events leading from the synthesis of the primary transcript to the spliced product can be divided into distinct steps: there must exist mechanisms by which the distant splice sites are recognized, brought into proximity, and precisely aligned. This is a prerequisite for the actual chemical cleavage-ligation reactions which result in intron excision and exon ligation. In the case of the self-splicing RNAs the recognition alignment is accomplished by specific intramolecular base pairing interactions (cis-alignment) and the cleavage ligation is mediated by catalytic RNA sequences located within the intron (reviewed by Cech and Bass 1986). In contrast, nuclear pre- mRNA splicing, as studied in vitro, requires a multitude of transacting components. Recognition takes place by the specific binding of snRNPs to conserved pre-mRNA sequences. The U1 snRNP interacts with the 5’ splice site, the U2 snRNP with the branch site, and the U5 snRNP most likely with the 3’ splice site. There is compelling evidence that the mode of recognition of U1 snRNP operates via intermolecular base pairing between sequences at the 5’ end of the U1 snRNA and sequences at the 5’ splice sites of pre-mRNAs. Likewise it has been shown in S. cerevisiae that its U2 analog (LSR1 or snR20) recognizes the conserved branchpoint consensus via base pairing to an internal snRNA sequence. In contrast, the binding of U5 snRNP appears to be mediated by a specific protein which is able to recognize the polypyrimidine tract located immediately upstream of the 3’ splice sites. The U4/U6 particle, although participating in splicing, may not bind directly to pre-mRNA but may instead interact with the other snRNPs to fold the splicing complex into a specific spatial configuration which results in the precise alignment of the splice sites. The ordered and sequential binding of the major U- snRNPs to the pre-mRNA is mediated by additional protein factors and leads to the stepwise assembly of large multicomponent complexes called spliceosomes, the formation of which can be studied by sedimentation in velocity gradients or by electrophoresis in nondenaturing acrylamide gels.
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影响因子：
10.5
作者：
LIN, RJ;LUSTIG, AJ;ABELSON, J
通讯作者：
ABELSON, J
分离含有 U1、U2、U4、U5 和 U6 RNA 的小核核糖核蛋白。
DOI：
--
发表时间：
1983
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Hinterberger,M;Pettersson,I;Steitz,JA
通讯作者：
Steitz,JA
由 HeLa 细胞分离组分形成的 RNA 剪接产物与快速沉降的复合物相关。
DOI：
10.1073/pnas.83.4.887
发表时间：
1986
影响因子：
11.1
作者：
Perkins,KK;Furneaux,HM;Hurwitz,J
通讯作者：
Hurwitz,J
保守内含子序列的突变影响酵母剪接途径中的多个步骤，特别是剪接体的组装。
DOI：
10.1002/j.1460-2075.1986.tb04412.x
发表时间：
1986
期刊：
The EMBO journal
影响因子：
--
作者：
Vijayraghavan,U;Parker,R;Tamm,J;Iimura,Y;Rossi,J;Abelson,J;Guthrie,C
通讯作者：
Guthrie,C
富含 NG,NG-二甲基精氨酸的核仁硬皮病抗原（Mr = 34,000；pI，8.5）的纯化和部分表征。
DOI：
--
发表时间：
1985
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Lischwe,MA;Ochs,RL;Reddy,R;Cook,RG;Yeoman,LC;Tan,EM;Reichlin,M;Busch,H
通讯作者：
Busch,H