A BBP-Mud2p heterodimer mediates branchpoint recognition and influences splicing substrate abundance in budding yeast.
A BBP-Mud2p heterodimer mediates branchpoint recognition and influences splicing substrate abundance in budding yeast.
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BBP-MUD2P异二聚体介导了分支点的识别，并影响萌芽酵母中的剪接底物丰度。
DOI：
10.1093/nar/gkn144
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发表时间：
2008-05
影响因子：
14.9
通讯作者：
Rymond, Brian C.
中科院分区：
文献类型：
--
作者：
Wang, Qiang;Zhang, Li;Lynn, Bert;Rymond, Brian C.
哺乳动物内含子的 3' 末端由分支点结合蛋白 SF1 和与相邻序列结合的 U2AF65-U2AF35 异二聚体标记。面包酵母具有等效的蛋白质、分支点结合蛋白 (BBP) (SF1) 和 Mud2p (U2AF65)，但缺乏明显的 U2AF35 同源物，从而留下了在剪接体组装过程中是否有另一种蛋白质替代的问题。使用凝胶过滤、亲和选择和质谱分析表明，Mud2p 与 BBP 形成复合物而不需要第三个（U2AF35 样）因子，而不是 U2AF65/U2AF35 样异二聚体。使用 MUD2 和 BBP 的突变体，我们发现 BBP-Mud2p 复合物桥接了伴侣特异性的 Prp39p、Mer1p、Clf1p 和 Smy2p 两种杂交相互作用。除了抑制 Mud2p 关联之外，bbpΔ56 突变还会损害剪接，增强前体 mRNA 从细胞核的释放，并且与 mud2::KAN 敲除类似，抑制致命的 sub2::KAN 突变。出乎意料的是，mud2::KAN 突变并没有加剧 bbpΔ56，而是部分抑制了 bbpΔ56 中观察到的前 mRNA 积累缺陷。我们提出 BBP-Mud2p 异二聚体作为一个单元与体内分支点结合，并在剪接体组装过程中作为 Sub2p-DExD/H-box ATPase 和其他剪接因子的靶标。此外，我们的结果表明 Mud2p 可能会增强 BBP-分支点关联受损的前 mRNA 的周转。
The 3′ end of mammalian introns is marked by the branchpoint binding protein, SF1, and the U2AF65-U2AF35 heterodimer bound at an adjacent sequence. Baker's yeast has equivalent proteins, branchpoint binding protein (BBP) (SF1) and Mud2p (U2AF65), but lacks an obvious U2AF35 homolog, leaving open the question of whether another protein substitutes during spliceosome assembly. Gel filtration, affinity selection and mass spectrometry were used to show that rather than a U2AF65/U2AF35-like heterodimer, Mud2p forms a complex with BBP without a third (U2AF35-like) factor. Using mutants of MUD2 and BBP, we show that the BBP–Mud2p complex bridges partner-specific Prp39p, Mer1p, Clf1p and Smy2p two-hybrid interactions. In addition to inhibiting Mud2p association, the bbpΔ56 mutation impairs splicing, enhances pre-mRNA release from the nucleus, and similar to a mud2::KAN knockout, suppresses a lethal sub2::KAN mutation. Unexpectedly, rather than exacerbating bbpΔ56, the mud2::KAN mutation partially suppresses a pre-mRNA accumulation defect observed with bbpΔ56. We propose that a BBP–Mud2p heterodimer binds as a unit to the branchpoint in vivo and serves as a target for the Sub2p-DExD/H-box ATPase and for other splicing factors during spliceosome assembly. In addition, our results suggest the possibility that the Mud2p may enhance the turnover of pre-mRNA with impaired BBP-branchpoint association.
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影响因子：
64.5
作者：
Berglund, JA;Chua, K;Rosbash, M
通讯作者：
Rosbash, M
影响因子：
12.3
作者：
Gama-Carvalho, Margarida;Barbosa-Morais, Nuno L.;Carmo-Fonseca, Maria
通讯作者：
Carmo-Fonseca, Maria
影响因子：
11.4
作者：
Huang, T;Vilardell, J;Query, CC
通讯作者：
Query, CC
影响因子：
10.5
作者：
ABOVICH, N;LIAO, XLC;ROSBASH, M
通讯作者：
ROSBASH, M
影响因子：
2.6
作者：
Bialkowska, A;Kurlandzka, A
通讯作者：
Kurlandzka, A