Mechanism and Regulation of mRNA Export

mRNA输出的机制和调控

• 批准号: 7732890
• 负责人: RAVI DHAR
• 金额: $ 63.02万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7732890
• 关键词: 14-3-3 Family; BRCA2 gene; Biological Models; Cell Cycle; Cell Cycle Progression; Cell Nucleus; Cell physiology; Complex; Coupled; Cytoplasm; DNA Damage; DNA Repair; DNA damage checkpoint; Dimensions; Fission Yeast; Goals; In Vitro; Mediating; Messenger RNA; Mitosis; Mitotic; Molecular; Monitor; Nuclear; Nuclear Export; Nuclear Pore; Nuclear Pore Complex; Organism; Process; Proteins; RNA; RNA Helicase; Recruitment Activity; Regulation; Reporting; Role; Site; Source; Time; Transcript; Translating; base; in vivo; mRNA Export; member; prevent; ras-GRF1

The export of mRNA from the nucleus to the cytoplasm is a multistep process that is mediated by mRNA-protein complexes (mRNP). The formation of mRNP begins by recruitment of some mRNA export factors to the elongating transcripts followed by targeting of the mRNP to the nuclear pore complex (NPC). The mRNP-complex is then translocation through the NPC channel. Finally the mRNP-complex is dissembled in the cytoplasm so that the RNA can be translated and mRNA export factors are returned to the nucleus for another round of mRNA export. We found in contrast to other organisms, that in fission yeast Schizosaccharomyces pombe (S. pombe) the putative RNA-helicase Uap56p functions non-enzymatically in mRNA export. It has been shown to be released from the mRNP-complex in the nucleus, however, in S. pombe we found it to function as a carrier of mRNA from the nucleus to the cytoplasm. We also found that its export to the cytoplasm through the nuclear pore complex is mediated by directly interacting with the mRNA export factor Rae1p. We have also found that DNA-damage checkpoint protein Rad24p a member of the 14-3-3 family of proteins is involved in the nuclear export of mRNA in S. pombe. Rad24p interacted directly with mRNA export factor Rae1p and with BRCA-2 interacting protein Dss1p. Previously we had reported that Dss1p was also required for the nuclear export of mRNA. We have recently found that Rae1p also functions in monitoring DNA damage in G2 /M phase of the cell cycle. For the first time we found that Dss1p was required for the recruitment of DNA-damage checkpoint proteins Rad24p-Rae1p to the DSB site in vivo. In DNA-damage Rad24p is though to mediate nuclear export of Cdc25p a mitotic activator of Cdc2p. Interestingly, for the first time, we demonstrate that Cdc25p is also recruited to DSB break site upon DNA-damage and this recruitment is mediated by Rad24p. Rad24p mediated sequestration of Cdc25p onto DSB adds a new dimension to G2/M checkpoint control by first preventing Cdc25ps interaction with Cdc2p during DNA damage, and subsequently providing a nuclear source of Cdc25p for activating Cdc2p immediately upon completion of DNA repair. Our demonstration of direct physical interaction between Rae1p and Rad24p in vitro and Rad24p-dependent recruitment of Rae1p in vivo provides a plausible molecular basis for the role of Rae1p in cell cycle progression.

从细胞核向细胞质的导出mRNA是由mRNA-蛋白质复合物（MRNP）介导的多步过程。 MRNP的形成首先募集了一些mRNA输出因子向伸长的转录本，然后将MRNP靶向核孔复合物（NPC）。然后，MRNP复合物通过NPC通道易位。 最后将MRNP复合物散布在细胞质中，以便可以翻译RNA，并将mRNA输出因子返回到核中，以进行另一轮mRNA输出。我们发现与其他生物相反，在裂变酵母中，酵母酸酯（S. pombe）在mRNA导出中，假定的RNA-羟基酶UAP56P在MRNA导出中非酶的功能。已显示它可以从细胞核中的mRNP复合物中释放出来，但是，在pombe链球菌中，我们发现它是从细胞核到细胞质的mRNA的载体。我们还发现，通过与mRNA输出因子RAE1P相互作用，它通过核孔复合物出口到细胞质。我们还发现，DNA破坏检查点蛋白RAD24P A 14-3-3家族的蛋白质家族的成员参与了S. pombe的mRNA的核输出。 RAD24P与mRNA输出因子RAE1P直接相互作用，并与BRCA-2相互作用的蛋白DSS1P相互作用。 以前，我们已经报道了MRNA的核输出也需要DSS1P。我们最近发现，RAE1P还起作用，可在细胞周期的G2 /M期监测DNA损伤中。我们第一次发现DSS1P是募集DNA损伤检查点蛋白RAD24P-RAE1P到VIVO的DSB位点所必需的。在DNA损伤中，rad24p是介导Cdc25p的核输出Cdc2p的核输出。有趣的是，我们首次证明了CDC25P在DNA损伤时也被招募到DSB断裂部位，并且该募集是由RAD24P介导的。 RAD24P介导的CDC25P序列在DSB上介导的隔离，通过在DNA损伤期间首先防止CDC25PS与CDC2P相互作用，从而为G2/M检查点控制增加了一个新维度，然后在完成DNA修复后立即激活CDC2P的CDC25P的核源。我们证明了RAE1P和RAD24P在体内RAE1P募集的RAE1P和RAD24P之间的直接物理相互作用为RAE1P在细胞周期进程中的作用提供了合理的分子基础。

项目成果

Conserved nuclear export sequences in Schizosaccharomyces pombe Mex67 and human TAP function in mRNA export by direct nuclear pore interactions.

粟酒裂殖酵母 Mex67 中的保守核输出序列和人 TAP 通过直接核孔相互作用在 mRNA 输出中发挥作用。

• DOI: 10.1074/jbc.m309731200
• 发表时间: 2004
• 期刊: The Journal of biological chemistry
• 作者: Thakurta,AnjanG;Gopal,Ganesh;Yoon,JinHo;Saha,Tapas;Dhar,Ravi
• 通讯作者: Dhar,Ravi