Presence of multiple mRNA cycling sequence element-binding proteins in Crithidia fasciculata
Presence of multiple mRNA cycling sequence element-binding proteins in Crithidia fasciculata
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DOI：
10.1074/jbc.m304322200
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发表时间：
2003-07-18
影响因子：
4.8
通讯作者：
Ray, DS
中科院分区：
文献类型：
--
作者：
Mittra, B;Sinha, KM;Ray, DS
编码DNA代谢相关蛋白质的几种束状Crithidia fasciculata信使RNA的5 '-或3'-非翻译区中存在的共有序列已被证明是这些mRNA在细胞周期期间周期性积累所必需的。循环序列结合蛋白（cycling sequence binding protein，CSBP）是一种具有两个亚基CSBPA和CSBPB的蛋白质复合物，它能高度特异性地结合共有序列。CSBP的结合活性在细胞周期中与推定的靶mRNA水平平行变化。虽然CSBPA基因的破坏导致CSBPA和CSBPB的损失，推定的目标信息水平仍然继续在细胞周期中变化。在这些CSBPA无效突变体细胞中揭示了额外的和不同的结合活性的存在。这种称为CSBP II的活性也在野生型Crithidia细胞中表达。CSBP II对循环序列元件的结合特异性高于先前描述的CSBP复合物。与纯化的CSBP II相关的三种多肽显示与循环序列的特异性结合。这些蛋白质可能代表参与转录后调节的序列特异性RNA结合蛋白家族。
A consensus sequence present in the 5'- or 3'-untranslated regions of several Crithidia fasciculata messenger RNAs encoding proteins involved in DNA metabolism has been shown to be necessary for the periodic accumulation of these mRNAs during the cell cycle. A protein complex termed cycling sequence-binding protein (CSBP) has two subunits, CSBPA and CSBPB, and binds the consensus sequence with high specificity. The binding activity of CSBP was shown to vary during the cell cycle in parallel with the levels of putative target mRNAs. Although disruption of the CSBPA gene resulted in loss of both CSBPA and CSBPB, the putative target message levels still continued to vary during the cell cycle. The presence of an additional and distinct binding activity was revealed in these CSBPA null mutant cells. This activity, termed CSBP II, was also expressed in wild-type Crithidia cells. CSBP II has higher binding specificity for the cycling sequence element than the earlier described CSBP complex. Three polypeptides associated with purified CSBP II show specific binding to the cycling sequence. These proteins may represent a family of sequence-specific RNA-binding proteins involved in post-transcriptional regulation.