Rozenblatt-Rosen Orit, Nagaike Takashi, Francis Joshua M, Kaneko Syuzo, Glatt Karen A, Hughes Christina M, LaFramboise Thomas, Manley James L, Meyerson Matthew
Department of Medical Oncology, Dana-Farber Cancer Institute, and Harvard Medical School, Boston, MA 02115, USA.
Proc Natl Acad Sci U S A. 2009 Jan 20;106(3):755-60. doi: 10.1073/pnas.0812023106. Epub 2009 Jan 9.
The CDC73 tumor suppressor gene is mutationally inactivated in hereditary and sporadic parathyroid tumors. Its product, the Cdc73 protein, is a component of the RNA polymerase II and chromatin-associated human Paf1 complex (Paf1C). Here, we show that Cdc73 physically associates with the cleavage and polyadenylation specificity factor (CPSF) and cleavage stimulation factor (CstF) complexes that are required for the maturation of mRNA 3' ends in the cell nucleus. Immunodepletion experiments indicate that the Cdc73-CPSF-CstF complex is necessary for 3' mRNA processing in vitro. Microarray analysis of CDC73 siRNA-treated cells revealed INTS6, a gene encoding a subunit of the Integrator complex, as an in vivo Cdc73 target. Cdc73 depletion by siRNA resulted in decreased INTS6 mRNA abundance, and decreased association of CPSF and CstF subunits with the INTS6 locus. Our results suggest that Cdc73 facilitates association of 3' mRNA processing factors with actively-transcribed chromatin and support the importance of links between tumor suppression and mRNA maturation.
CDC73肿瘤抑制基因在遗传性和散发性甲状旁腺肿瘤中发生突变失活。其产物Cdc73蛋白是RNA聚合酶II和与染色质相关的人类Paf1复合物(Paf1C)的一个组成部分。在此,我们表明Cdc73与细胞核中mRNA 3'末端成熟所需的切割和聚腺苷酸化特异性因子(CPSF)及切割刺激因子(CstF)复合物发生物理结合。免疫去除实验表明,Cdc73-CPSF-CstF复合物在体外对3' mRNA加工是必需的。对经CDC73 siRNA处理的细胞进行微阵列分析,发现INTS6(一个编码整合子复合物亚基的基因)是Cdc73在体内的一个靶点。通过siRNA去除Cdc73导致INTS6 mRNA丰度降低,以及CPSF和CstF亚基与INTS6基因座的结合减少。我们的结果表明,Cdc73促进3' mRNA加工因子与活跃转录的染色质的结合,并支持肿瘤抑制与mRNA成熟之间联系的重要性。