Symplekin and multiple other polyadenylation factors participate in 3′-end maturation of histone mRNAs
Symplekin and multiple other polyadenylation factors participate in 3′-end maturation of histone mRNAs
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DOI：
10.1101/gad.1371105
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发表时间：
2005-11-01
影响因子：
10.5
通讯作者：
Steitz, JA
中科院分区：
文献类型：
--
作者：
Kolev, NG;Steitz, JA
大多数后生动物编码组蛋白的信使RNA被切割，但在它们的3'端不被多腺苷酸化。在哺乳动物细胞提取物中的处理需要U7小核核糖核蛋白（U7 snRNP）和一种未鉴定的热不稳定因子（HLF）。我们描述了一种热敏蛋白复合物的鉴定，其完整性是组蛋白前mRNA切割所需的。它包括切割和多聚腺苷酸化特异性因子（CPSF）的所有五个亚基，切割刺激因子（CstF）的两个亚基和symplekin。重建实验表明，symplekin，以前被证明是必要的细胞质聚（A）尾伸长和翻译激活的mRNA在非洲爪蟾卵母细胞成熟，是必不可少的热不稳定的组成部分。因此，共同的分子机制有助于缺乏和拥有poly（A）的mRNA的核成熟，以及细胞质poly（A）尾延伸。
Most metazoan messenger RNAs encoding histones are cleaved, but not polyadenylated at their 3' ends. Processing in mammalian cell extracts requires the U7 small nuclear ribonucleoprotein (U7 snRNP) and an unidentified heat-labile factor (HLF). We describe the identification of a heat-sensitive protein complex whose integrity is required for histone pre-mRNA cleavage. It includes all five subunits of the cleavage and polyadenylation specificity factor (CPSF), two subunits of the cleavage stimulation factor (CstF), and symplekin. Reconstitution experiments reveal that symplekin, previously shown to be necessary for cytoplasmic poly(A) tail elongation and translational activation of mRNAs during Xenopus oocyte maturation, is the essential heat-labile component. Thus, a common molecular machinery contributes to the nuclear maturation of mRNAs both lacking and possessing poly(A), as well as to cytoplasmic poly(A) tail elongation.