Department of Chemistry, Hunter College, City University of New York, New York, NY, USA.
EMBO J. 2010 May 19;29(10):1674-87. doi: 10.1038/emboj.2010.59. Epub 2010 Apr 8.
We previously showed that mRNA 3' end cleavage reaction in cell extracts is strongly but transiently inhibited under DNA-damaging conditions. The cleavage stimulation factor-50 (CstF-50) has a role in this response, providing a link between transcription-coupled RNA processing and DNA repair. In this study, we show that CstF-50 interacts with nuclear poly(A)-specific ribonuclease (PARN) using in vitro and in extracts of UV-exposed cells. The CstF-50/PARN complex formation has a role in the inhibition of 3' cleavage and activation of deadenylation upon DNA damage. Extending these results, we found that the tumour suppressor BARD1, which is involved in the UV-induced inhibition of 3' cleavage, strongly activates deadenylation by PARN in the presence of CstF-50, and that CstF-50/BARD1 can revert the cap-binding protein-80 (CBP80)-mediated inhibition of PARN activity. We also provide evidence that PARN along with the CstF/BARD1 complex participates in the regulation of endogenous transcripts under DNA-damaging conditions. We speculate that the interplay between polyadenylation, deadenylation and tumour-suppressor factors might prevent the expression of prematurely terminated messengers, contributing to control of gene expression under different cellular conditions.
我们之前曾表明，在 DNA 损伤条件下，细胞提取物中的 mRNA 3' 端切割反应会强烈但短暂地受到抑制。切割刺激因子-50（CstF-50）在这一反应中起作用，为转录偶联的 RNA 加工和 DNA 修复之间提供了联系。在这项研究中，我们使用体外实验和 UV 暴露细胞提取物表明 CstF-50 与核多聚（A）特异性核糖核酸酶（PARN）相互作用。CstF-50/PARN 复合物的形成在 3' 切割的抑制和 DNA 损伤时的脱腺苷酸化的激活中起作用。扩展这些结果，我们发现肿瘤抑制因子 BARD1 参与了 UV 诱导的 3' 切割抑制，在 CstF-50 的存在下，PARN 强烈地激活脱腺苷酸化，并且 CstF-50/BARD1 可以逆转帽结合蛋白-80（CBP80）介导的 PARN 活性抑制。我们还提供了证据表明 PARN 与 CstF/BARD1 复合物一起参与了 DNA 损伤条件下内源性转录本的调节。我们推测，多聚腺苷酸化、脱腺苷酸化和肿瘤抑制因子之间的相互作用可能阻止过早终止信使的表达，有助于在不同细胞条件下控制基因表达。
