Regulation of retention of FosB intron 4 by PTB.
Regulation of retention of FosB intron 4 by PTB.
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DOI：
10.1371/journal.pone.0000828
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发表时间：
2007-09-05
期刊：
影响因子：
3.7
通讯作者：
Potashkin JA
中科院分区：
文献类型：
--
作者：
Marinescu V;Loomis PA;Ehmann S;Beales M;Potashkin JA
应激源（如慢性药物管理）的一个影响是转录因子FosB末端外显子内的序列被识别为内含子并通过选择性剪接去除。这导致开放阅读框移位，产生翻译停止密码子，最终产生截断蛋白，称为ΔFosB。用一个fosB迷你基因构建物生成的对照转录本和突变转录本进行的体外剪接实验表明，内含子4 (I4) 3 '端富含cu的序列与多聚嘧啶束结合蛋白（PTB）结合，在调节fosB pre-mRNA剪接中起重要作用。PTB与该序列的结合依赖于蛋白激酶A的磷酸化，如果富cu序列突变为富u区域，PTB将被阻断。当这种突变的fosB基因在HeLa细胞中表达时，其产物的剪接效率比野生型高。此外，在HeLa细胞中短暂转染PTB-1降低了野生型fosB迷你基因转录物的剪接效率。核提取物中PTB的缺失促进了U2AF65在体外与野生型序列的结合，表明这些蛋白在动态平衡中调节fosB pre-mRNA选择性剪接。这些结果首次证明磷酸化的PTB促进内含子保留，从而沉默fosB I4的剪接。
One effect of stressors such as chronic drug administration is that sequence within the terminal exon of the transcription factor FosB is recognized as intronic and removed by alternative splicing. This results in an open-reading-frame shift that produces a translation stop codon and ultimately a truncated protein, termed ΔFosB. In vitro splicing assays with control and mutated transcripts generated from a fosB mini-gene construct indicated a CU-rich sequence at the 3′ end of intron 4 (I4) plays an important role in regulating fosB pre-mRNA splicing due to its binding of polypyrimidine tract binding protein (PTB). PTB binding to this sequence is dependent upon phosphorylation by protein kinase A and is blocked if the CU-rich sequence is mutated to a U-rich region. When this mutated fosB minigene is expressed in HeLa cells, the splicing efficiency of its product is increased compared to wild type. Moreover, transient transfection of PTB-1 in HeLa cells decreased the splicing efficiency of a wild type fosB minigene transcript. Depletion of PTB from nuclear extracts facilitated U2AF65 binding to wild type sequence in vitro, suggesting these proteins function in a dynamic equilibrium to modulate fosB pre-mRNA alternative splicing. These results demonstrate for the first time that phosphorylated PTB promotes intron retention and thereby silences the splicing of fosB I4.
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影响因子：
2.9
作者：
Alibhai, Imran N.;Green, Thomas A.;Nestler, Eric J.
通讯作者：
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影响因子：
4.5
作者：
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影响因子：
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作者：
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通讯作者：
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DOI：
10.1016/s0169-328x(01)00072-9
发表时间：
2001-05-20
期刊：
MOLECULAR BRAIN RESEARCH
影响因子：
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作者：
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通讯作者：
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影响因子：
5.3
作者：
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通讯作者：
Black, DL