An SC35-like protein and a novel serine/arginine-rich protein interact with Arabidopsis U1-70K protein
An SC35-like protein and a novel serine/arginine-rich protein interact with Arabidopsis U1-70K protein
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DOI：
10.1074/jbc.274.51.36428
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发表时间：
1999-12-17
影响因子：
4.8
通讯作者：
Reddy, ASN
中科院分区：
文献类型：
--
作者：
Golovkin, M;Reddy, ASN
U1小核核糖核蛋白70-kDa蛋白是一种U1小核核糖核蛋白特异性蛋白，已被证明在动物核前体mRNA加工中具有多种作用。利用拟南芥U1 - 110 Ⅱ蛋白C端富含丝氨酸的区域，在酵母双杂交系统中，我们鉴定了一个与植物U1- 70 K相互作用的类SC 35蛋白（SR 33）和一个新的植物富含丝氨酸/丝氨酸（SR）的蛋白（SR 45）。SR 33和SR 45蛋白与SR蛋白有几个共同的特征，包括SR蛋白家族中剪接因子的典型模块结构域。然而，这两种植物SR蛋白都富含脯氨酸，并且与大多数动物SR蛋白不同，SR 45具有由RNA识别基序分开的两个不同的富含精氨酸/丝氨酸的结构域。通过共沉淀实验，我们证实了植物U1- 70 K与SR 33和SR 45蛋白的相互作用。此外，体内和体外蛋白质-蛋白质相互作用实验表明，SR 33蛋白与其自身和SR 45蛋白相互作用，但不与已知仅与拟南芥全长U-70 H相互作用的SR家族的另外两个成员（SRZ 21和SRZ 22）相互作用。来自拟南芥的Clk/Sty蛋白激酶（AFC-8）磷酸化四种SR蛋白（SR 33、SR 45、SRZ 21和SRZ 22）。共沉淀研究已经证实了SR蛋白与AFC 2激酶的相互作用，并且AFC 2和SR 33之间的相互作用受到这些蛋白的磷酸化状态的调节。这些和我们以前的研究结果表明，植物U1- 70 B：相互作用与SR家族的至少四个不同的成员，包括SR 45与其两个精氨酸/丝氨酸丰富的结构域，和SR蛋白和AFC 2之间的相互作用是由磷酸化调节。植物U1- 70 K与一组新蛋白质的相互作用表明剪接体组装的早期阶段，植物中的内含子识别可能不同于动物。
The U1 small nuclear ribonucleoprotein 70-kDa protein, a U1 small nuclear ribonucleoprotein-specific protein, has been shown to have multiple roles in nuclear precursor mRNA processing in animals. By using the C-terminal arginine-rich region of Arabidopsis U1-'IOII protein in the yeast two-hybrid system, we have identified an SC35-like (SR33) and a novel plant serine/arginine-rich (SR) protein (SR45) that interact with the plant U1-70K The SR33 and SR45 proteins share several features with SR proteins including modular domains typical of splicing factors in the SR family of proteins. However, both plant SR proteins are rich in proline, and SR45, unlike most animal SR proteins, has two distinct arginine/serine-rich domains separated by an RNA recognition motif. By using coprecipitation assays we confirmed the interaction of plant U1-70K with SR33 and SR45 proteins. Furthermore, in vivo and in vitro protein-protein interaction experiments have shown that SR33 protein interacts with itself and with SR45 protein but not with two other members (SRZ21 and SRZ22) of the SR family that are known to interact with the Arabidopsis full-length U-70H only. A Clk/Sty protein kinase (AFC-8) from Arabidopsis phosphorylated four SR proteins (SR33, SR45, SRZ21, and SRZ22). Coprecipitation studies have confirmed the interaction of SR proteins with AFC2 kinase, and the interaction between AFC2 and SR33 is modulated by the phosphorylation status of these proteins. These and our previous results suggest that the plant U1-70B: interacts with at least four distinct members of the SR family including SR45 with its two arginine/serine-rich domains, and the interaction between the SR proteins and AFC2 is modulated by phosphorylation. The interaction of plant U1-70K with a novel set of proteins suggests the early stages of spliceosome assembly, and intron recognition in plants is likely to be different from animals.