Reconstitution of CPSF active in polyadenylation: recognition of the polyadenylation signal by WDR33
GENES & DEVELOPMENT
Authors: Schoenemann, Lars; Kuehn, Uwe; Martin, Georges; Schaefer, Peter; Gruber, Andreas R.; Keller, Walter; Zavolan, Mihaela; Wahle, Elmar
Abstract
Cleavage and polyadenylation specificity factor (CPSF) is the central component of the 3' processing machinery for polyadenylated mRNAs in metazoans: CPSF recognizes the polyadenylation signal AAUAAA, providing sequence specificity in both pre-mRNA cleavage and polyadenylation, and catalyzes pre-mRNA cleavage. Here we show that of the seven polypeptides that have been proposed to constitute CPSF, only four (CPSF160, CPSF30, hFip1, and WDR33) are necessary and sufficient to reconstitute a CPSF subcomplex active in AAUAAA-dependent polyadenylation, whereas CPSF100, CPSF73, and symplekin are dispensable. WDR33 is required for binding of reconstituted CPSF to AAUAAA-containing RNA and can be specifically UV cross-linked to such RNAs, as can CPSF30. Transcriptome-wide identification of WDR33 targets by photoactivatable ribonucleoside-enhanced cross-linking and immunoprecipitation (PAR-CLIP) showed that WDR33 binds in and very close to the AAUAAA signal in vivo with high specificity. Thus, our data indicate that the large CPSF subunit participating in recognition of the polyadenylation signal is WDR33 and not CPSF160, as suggested by previous studies.
Circulating essential metals and lung cancer: Risk assessment and potential molecular effects
ENVIRONMENT INTERNATIONAL
Authors: Bai, Yansen; Wang, Gege; Fu, Wenshan; Lu, Yanjun; Wei, Wei; Chen, Weilin; Wu, Xiulong; Meng, Hua; Feng, Yue; Liu, Yuhang; Li, Guyanan; Wang, Suhan; Wang, Ke; Dai, Juanxiu; Li, Hang; Li, Mengying; Huang, Jiao; Li, Yangkai; Wei, Sheng; Yuan, Jing; Yao, Ping; Miao, Xiaoping; He, Meian; Zhang, Xiaomin; Yang, Handong; Wu, Tangchun; Guo, Huan
Abstract
Objective: Essential metals play important roles in the carcinogenic process. However, seldom longitudinal investigations have evaluated their roles in lung cancer development. We aimed to investigate the associations between multiple essential metals and lung cancer incidence and to explore the potential mechanisms. Methods: A nested case-control study of 440 incident lung cancer cases and 1: 3 frequency matched 1320 healthy controls from the Dongfeng-Tongji Cohort was conducted. The baseline plasma concentrations of 11 essential metals (cobalt, copper, iron, manganese, molybdenum, rubidium, selenium, strontium, stannum, vanadium, and zinc) were measured, and their associations with lung cancer incidence were estimated. Effect of positive metal (zinc) on 4-year telomere attrition was then evaluated among an occupational cohort of 724 workers. We also assessed the transcriptional regulation effects of plasma zinc on mRNA expression profiles, and the expressions of zinc-related genes were further compared in pair-wised lung tumor and normal tissues. Results: Elevated plasma level of zinc was associated with lower incident risk of lung cancer [OR (95% CI) = 0.89 (0.79, 0.99)] and decreased 4-year telomere attrition [beta (95% CI) = -0.73 (-1.27, -0.19)]. These effects were pronounced among males. In particularly, zinc could regulate the expressions of 8 cancer-related genes, including SOD1, APE, TP53BP1, WDR33, LAPTM4B, TRIT1, HUWE1, and ZNF813, which were over-expressed in lung tumor tissues. Conclusions: We propose that high plasma zinc could prevent incident lung cancer, probably by slowing down telomere attrition and regulating the expressions of cancer-related genes. These results provided a new insight into lung cancer prevention.