1
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Song Y, Wang L, Xu M, Lu X, Wang Y, Zhang L. Molecular and functional characterization of porcine poly C binding protein 1 (PCBP1). BMC Vet Res 2024; 20:25. [PMID: 38218813 PMCID: PMC10787444 DOI: 10.1186/s12917-023-03861-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 12/20/2023] [Indexed: 01/15/2024] Open
Abstract
BACKGROUND Poly C Binding Protein 1 (PCBP1) belongs to the heterogeneous nuclear ribonucleoprotein family. It is a multifunctional protein that participates in several functional circuits and plays a variety of roles in cellular processes. Although PCBP1 has been identified in several mammals, its function in porcine was unclear. RESULTS In this study, we cloned the gene of porcine PCBP1 and analyzed its evolutionary relationships among different species. We found porcine PCBP1 protein sequence was similar to that of other animals. The subcellular localization of PCBP1 in porcine kidney cells 15 (PK-15) cells was analyzed by immunofluorescence assay (IFA) and revealed that PCBP1 was mainly localized to the nucleus. Reverse transcription-quantitative PCR (RT-qPCR) was used to compare PCBP1 mRNA levels in different tissues of 30-day-old pigs. Results indicated that PCBP1 was expressed in various tissues and was most abundant in the liver. Finally, the effects of PCBP1 on cell cycle and apoptosis were investigated following its overexpression or knockdown in PK-15 cells. The findings demonstrated that PCBP1 knockdown arrested cell cycle in G0/G1 phase, and enhanced cell apoptosis. CONCLUSIONS Porcine PCBP1 is a highly conserved protein, plays an important role in determining cell fate, and its functions need further study.
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Affiliation(s)
- Yue Song
- Molecule Biology Laboratory of Zhengzhou Normal University, Zhengzhou Henan, 450044, China
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, 450046, China
| | - Linqing Wang
- Molecule Biology Laboratory of Zhengzhou Normal University, Zhengzhou Henan, 450044, China.
| | - Menglong Xu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, 450046, China
| | - Xiuxiang Lu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, 450046, China
| | - Yumin Wang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, 450046, China
| | - Limeng Zhang
- Molecule Biology Laboratory of Zhengzhou Normal University, Zhengzhou Henan, 450044, China
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2
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Luo Y, Zhang Y, Pang S, Min J, Wang T, Wu D, Lin C, Xiao Z, Xiang Q, Li Q, Ma L. PCBP1 protects bladder cancer cells from mitochondria injury and ferroptosis by inducing LACTB mRNA degradation. Mol Carcinog 2023. [PMID: 37157950 DOI: 10.1002/mc.23533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 03/02/2023] [Accepted: 03/13/2023] [Indexed: 05/10/2023]
Abstract
Although Poly C Binding Protein 1 (PCBP1) affects cellular ferroptosis and mitochondrial dysfunction, the mechanisms by which PCBP1 regulates bladder cancer (BC) cell functions are unknown. In this study, two BC cell lines (T24 and UMUC3) were treated with different doses of ferroptosis inducer erastin to analyze the effect of PCBP1. Online databases (RPISeq and CatRAPID) were used to predict the possible direct interaction between PCBP1 protein and serine β-lactamase-like protein (LACTB) mRNA, which was further validated via RNA pull-down, RNA immunoprecipitation, and luciferase reporter assays. Mitochondria injury and ferroptosis were evaluated using CCK-8 assay, TUNEL staining, flow cytometry, corresponding kits, and JC-1 staining. In vivo experiments were conducted using tumor xenograft models. Quantitative reverse-transcription polymerase chain reaction was used to detect transcript expression levels, while protein levels were analyzed using western blot and immunohistochemistry. PCBP1 expression was significantly upregulated in BC tissues and cell lines. Also, PCBP1 knockdown increased erastin-mediated ferroptosis in T24 and UMUC3 cells, while PCBP1 overexpression decreased erastin-mediated ferroptosis in T24 and UMUC3 cells. Mechanistic results showed that LACTB mRNA is a novel PCBP1-binding transcript. LACTB upregulation promoted erastin-induced ferroptosis and mitochondrial dysfunction. Furthermore, LACTB overexpression reversed PCBP1-mediated ferroptosis protection, including decreased ROS and enhanced mitochondrial function, which were further alleviated after phosphatidylserine decarboxylase (PISD) overexpression. Moreover, PCBP1 silencing significantly enhanced tumor inhibition effect of sulfasalazine in xenograft mice transplanted with T24 and UMUC3 cells, leading to LACTB upregulation and PISD downregulation. In conclusion, PCBP1 protects BC cells against mitochondria injury and ferroptosis via LACTB/PISD axis.
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Affiliation(s)
- Yang Luo
- Department of Urology, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou, China
| | - Yunli Zhang
- Department of Pathology, Nanfang Hospital and School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Shiyu Pang
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jingxian Min
- Department of Health Management, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Tao Wang
- Department of Urology, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou, China
| | - Dali Wu
- Department of Urology, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou, China
| | - Chun Lin
- Department of Pathology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Zebin Xiao
- Department of Pathology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Qi Xiang
- Department of Urology, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou, China
| | - Qing Li
- Department of Urology, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou, China
| | - Lili Ma
- Department of Pathology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
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3
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Zhao H, Wei Z, Shen G, Chen Y, Hao X, Li S, Wang R. Poly(rC)-binding proteins as pleiotropic regulators in hematopoiesis and hematological malignancy. Front Oncol 2022; 12:1045797. [PMID: 36452487 PMCID: PMC9701828 DOI: 10.3389/fonc.2022.1045797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/26/2022] [Indexed: 11/16/2022] Open
Abstract
Poly(rC)-binding proteins (PCBPs), a defined subfamily of RNA binding proteins, are characterized by their high affinity and sequence-specific interaction with poly-cytosine (poly-C). The PCBP family comprises five members, including hnRNP K and PCBP1-4. These proteins share a relatively similar structure motif, with triple hnRNP K homology (KH) domains responsible for recognizing and combining C-rich regions of mRNA and single- and double-stranded DNA. Numerous studies have indicated that PCBPs play a prominent role in hematopoietic cell growth, differentiation, and tumorigenesis at multiple levels of regulation. Herein, we summarized the currently available literature regarding the structural and functional divergence of various PCBP family members. Furthermore, we focused on their roles in normal hematopoiesis, particularly in erythropoiesis. More importantly, we also discussed and highlighted their involvement in carcinogenesis, including leukemia and lymphoma, aiming to clarify the pleiotropic roles and molecular mechanisms in the hematopoietic compartment.
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Affiliation(s)
- Huijuan Zhao
- Henan International Joint Laboratory of Thrombosis and Hemostasis, Henan University of Science and Technology, Luoyang, China.,Basic Medical College, Henan University of Science and Technology, Luoyang, China
| | - Ziqing Wei
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Guomin Shen
- Henan International Joint Laboratory of Thrombosis and Hemostasis, Henan University of Science and Technology, Luoyang, China.,Basic Medical College, Henan University of Science and Technology, Luoyang, China
| | - Yixiang Chen
- Henan International Joint Laboratory of Thrombosis and Hemostasis, Henan University of Science and Technology, Luoyang, China.,Basic Medical College, Henan University of Science and Technology, Luoyang, China
| | - Xueqin Hao
- Basic Medical College, Henan University of Science and Technology, Luoyang, China
| | - Sanqiang Li
- Basic Medical College, Henan University of Science and Technology, Luoyang, China
| | - Rong Wang
- Department of Clinical Laboratory, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, China
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4
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RNA-Binding Proteins PCBP1 and PCBP2 Are Critical Determinants of Murine Erythropoiesis. Mol Cell Biol 2021; 41:e0066820. [PMID: 34180713 PMCID: PMC8384066 DOI: 10.1128/mcb.00668-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We previously demonstrated that the two paralogous RNA-binding proteins PCBP1 and PCBP2 are individually essential for mouse development: Pcbp1-null embryos are peri-implantation lethal, while Pcbp2-null embryos lose viability at midgestation. Midgestation Pcbp2-/- embryos revealed a complex phenotype that included loss of certain hematopoietic determinants. Whether PCBP2 directly contributes to erythropoietic differentiation and whether PCBP1 has a role in this process remained undetermined. Here, we selectively inactivated the genes encoding these two RNA-binding proteins during differentiation of the erythroid lineage in the developing mouse embryo. Individual inactivation of either locus failed to impact viability or blood formation. However, combined inactivation of the two loci resulted in midgestational repression of erythroid/hematopoietic gene expression, loss of blood formation, and fetal demise. Orthogonal ex vivo analyses of primary erythroid progenitors selectively depleted of these two RNA-binding proteins revealed that they mediate a combination of overlapping and isoform-specific impacts on hematopoietic lineage transcriptome, impacting both mRNA representation and exon splicing. These data lead us to conclude that PCBP1 and PCBP2 mediate functions critical to differentiation of the erythroid lineage.
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5
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The iron chaperone and nucleic acid-binding activities of poly(rC)-binding protein 1 are separable and independently essential. Proc Natl Acad Sci U S A 2021; 118:2104666118. [PMID: 34161287 DOI: 10.1073/pnas.2104666118] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Poly(rC)-binding protein (PCBP1) is a multifunctional adaptor protein that can coordinate single-stranded nucleic acids and iron-glutathione complexes, altering the processing and transfer of these ligands through interactions with other proteins. Multiple phenotypes are ascribed to cells lacking PCBP1, but the relative contribution of RNA, DNA, or iron chaperone activity is not consistently clear. Here, we report the identification of amino acid residues required for iron coordination on each structural domain of PCBP1 and confirm the requirement of iron coordination for binding target proteins BolA2 and ferritin. We further construct PCBP1 variants that lack either nucleic acid- or iron-binding activity and examine their functions in human cells and mouse tissues depleted of endogenous PCBP1. We find that these activities are separable and independently confer essential functions. While iron chaperone activity controls cell cycle progression and suppression of DNA damage, RNA/DNA-binding activity maintains cell viability in both cultured cell and mouse models. The coevolution of RNA/DNA binding and iron chaperone activities on a single protein may prove advantageous for nucleic acid processing that depends on enzymes with iron cofactors.
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6
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Porter DF, Miao W, Yang X, Goda GA, Ji AL, Donohue LKH, Aleman MM, Dominguez D, Khavari PA. easyCLIP analysis of RNA-protein interactions incorporating absolute quantification. Nat Commun 2021; 12:1569. [PMID: 33692367 PMCID: PMC7946914 DOI: 10.1038/s41467-021-21623-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 01/26/2021] [Indexed: 12/20/2022] Open
Abstract
Quantitative criteria to identify proteins as RNA-binding proteins (RBPs) are presently lacking, as are criteria to define RBP target RNAs. Here, we develop an ultraviolet (UV) cross-linking immunoprecipitation (CLIP)-sequencing method, easyCLIP. easyCLIP provides absolute cross-link rates, as well as increased simplicity, efficiency, and capacity to visualize RNA libraries during sequencing library preparation. Measurement of >200 independent cross-link experiments across >35 proteins identifies an RNA cross-link rate threshold that distinguishes RBPs from non-RBPs and defines target RNAs as those with a complex frequency unlikely for a random protein. We apply easyCLIP to the 33 most recurrent cancer mutations across 28 RBPs, finding increased RNA binding per RBP molecule for KHDRBS2 R168C, A1CF E34K and PCBP1 L100P/Q cancer mutations. Quantitating RBP-RNA interactions can thus nominate proteins as RBPs and define the impact of specific disease-associated RBP mutations on RNA association.
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Affiliation(s)
- Douglas F. Porter
- grid.168010.e0000000419368956Program in Epithelial Biology, Stanford University, Stanford, CA USA ,grid.168010.e0000000419368956Stanford Program in Cancer Biology, Stanford University, Stanford, CA USA
| | - Weili Miao
- grid.168010.e0000000419368956Program in Epithelial Biology, Stanford University, Stanford, CA USA ,grid.168010.e0000000419368956Stanford Program in Cancer Biology, Stanford University, Stanford, CA USA
| | - Xue Yang
- grid.168010.e0000000419368956Program in Epithelial Biology, Stanford University, Stanford, CA USA ,grid.168010.e0000000419368956Stanford Program in Cancer Biology, Stanford University, Stanford, CA USA
| | - Grant A. Goda
- grid.10698.360000000122483208Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC USA ,grid.10698.360000000122483208Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC USA
| | - Andrew L. Ji
- grid.168010.e0000000419368956Program in Epithelial Biology, Stanford University, Stanford, CA USA ,grid.168010.e0000000419368956Stanford Program in Cancer Biology, Stanford University, Stanford, CA USA
| | - Laura K. H. Donohue
- grid.168010.e0000000419368956Program in Epithelial Biology, Stanford University, Stanford, CA USA ,grid.168010.e0000000419368956Department of Genetics, Stanford University, Stanford, CA USA
| | - Maria M. Aleman
- grid.10698.360000000122483208Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC USA
| | - Daniel Dominguez
- grid.10698.360000000122483208Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC USA ,grid.10698.360000000122483208Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC USA
| | - Paul A. Khavari
- grid.168010.e0000000419368956Program in Epithelial Biology, Stanford University, Stanford, CA USA ,grid.168010.e0000000419368956Stanford Program in Cancer Biology, Stanford University, Stanford, CA USA ,Veterans Affairs, Palo Alto Healthcare System, Palo Alto, CA USA
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7
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Cai J, Wang N, Lin G, Zhang H, Xie W, Zhang Y, Xu N. MBNL2 Regulates DNA Damage Response via Stabilizing p21. Int J Mol Sci 2021; 22:ijms22020783. [PMID: 33466733 PMCID: PMC7829980 DOI: 10.3390/ijms22020783] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/31/2020] [Accepted: 01/12/2021] [Indexed: 12/14/2022] Open
Abstract
RNA-binding proteins are frequently dysregulated in human cancer and able to modulate tumor cell proliferation as well as tumor metastasis through post-transcriptional regulation on target genes. Abnormal DNA damage response and repair mechanism are closely related to genome instability and cell transformation. Here, we explore the function of the RNA-binding protein muscleblind-like splicing regulator 2 (MBNL2) on tumor cell proliferation and DNA damage response. Transcriptome and gene expression analysis show that the PI3K/AKT pathway is enriched in MBNL2-depleted cells, and the expression of cyclin-dependent kinase inhibitor 1A (p21CDKN1A) is significantly affected after MBNL2 depletion. MBNL2 modulates the mRNA and protein levels of p21, which is independent of its canonical transcription factor p53. Moreover, depletion of MBNL2 increases the phosphorylation levels of checkpoint kinase 1 (Chk1) serine 345 (S345) and DNA damage response, and the effect of MBNL2 on DNA damage response is p21-dependent. MBNL2 would further alter tumor cell fate after DNA damage, MBNL2 knockdown inhibiting DNA damage repair and DNA damage-induced senescence, but promoting DNA damage-induced apoptosis.
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Affiliation(s)
- Jin Cai
- State Key Laboratory of Chemical Oncogenomics, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (J.C.); (N.W.); (G.L.); (H.Z.); (W.X.); (Y.Z.)
- Open FIESTA Center, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Ningchao Wang
- State Key Laboratory of Chemical Oncogenomics, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (J.C.); (N.W.); (G.L.); (H.Z.); (W.X.); (Y.Z.)
- Open FIESTA Center, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Guanglan Lin
- State Key Laboratory of Chemical Oncogenomics, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (J.C.); (N.W.); (G.L.); (H.Z.); (W.X.); (Y.Z.)
- Open FIESTA Center, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Haowei Zhang
- State Key Laboratory of Chemical Oncogenomics, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (J.C.); (N.W.); (G.L.); (H.Z.); (W.X.); (Y.Z.)
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Weidong Xie
- State Key Laboratory of Chemical Oncogenomics, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (J.C.); (N.W.); (G.L.); (H.Z.); (W.X.); (Y.Z.)
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Yaou Zhang
- State Key Laboratory of Chemical Oncogenomics, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (J.C.); (N.W.); (G.L.); (H.Z.); (W.X.); (Y.Z.)
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Naihan Xu
- State Key Laboratory of Chemical Oncogenomics, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (J.C.); (N.W.); (G.L.); (H.Z.); (W.X.); (Y.Z.)
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- Correspondence:
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8
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Zhang X, Di C, Chen Y, Wang J, Su R, Huang G, Xu C, Chen X, Long F, Yang H, Zhang H. Multilevel regulation and molecular mechanism of poly (rC)-binding protein 1 in cancer. FASEB J 2020; 34:15647-15658. [PMID: 33058239 DOI: 10.1096/fj.202000911r] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 09/02/2020] [Accepted: 09/15/2020] [Indexed: 01/07/2023]
Abstract
Poly (rC)-binding protein 1 (PCBP1), an RNA- or DNA-binding protein with a relative molecular weight of 38 kDa, which is characterized by downregulation in many cancer types. Numerous cases have indicated that PCBP1 could be considered as a tumor suppressor to inhibit tumorigenesis, development, and metastasis. In the current review, we described the multilevel regulatory roles of PCBP1, including gene transcription, alternative splicing, and translation of many cancer-related genes. Additionally, we also provided a brief overview about the inhibitory effect of PCBP1 on most common tumors. More importantly, we summarized the current research status about PCBP1 in hypoxic microenvironment, autophagy, apoptosis, and chemotherapy of cancer cells, aiming to clarify the molecular mechanisms of PCBP1 in cancer. Taken together, in-depth study of PCBP1 in cancer may provide new ideas for cancer therapy.
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Affiliation(s)
- Xuetian Zhang
- Bio-Medical Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Cuixia Di
- Bio-Medical Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Yuhong Chen
- Bio-Medical Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Jing Wang
- School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Ruowei Su
- The First Affiliated Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Guomin Huang
- Bio-Medical Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Caipeng Xu
- Bio-Medical Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaohua Chen
- Bio-Medical Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Feng Long
- Gansu University of Traditional Chinese Medicine, Lanzhou, China
| | - Hongying Yang
- School of Radiation Medicine and Protection, Medical College of Soochow, Soochow, China
| | - Hong Zhang
- Bio-Medical Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing, China
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9
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Murphy MR, Kleiman FE. Connections between 3' end processing and DNA damage response: Ten years later. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1571. [PMID: 31657151 PMCID: PMC7295566 DOI: 10.1002/wrna.1571] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/10/2019] [Accepted: 09/17/2019] [Indexed: 12/23/2022]
Abstract
Ten years ago we reviewed how the cellular DNA damage response (DDR) is controlled by changes in the functional and structural properties of nuclear proteins, resulting in a timely coordinated control of gene expression that allows DNA repair. Expression of genes that play a role in DDR is regulated not only at transcriptional level during mRNA biosynthesis but also by changing steady-state levels due to turnover of the transcripts. The 3' end processing machinery, which is important in the regulation of mRNA stability, is involved in these gene-specific responses to DNA damage. Here, we review the latest mechanistic connections described between 3' end processing and DDR, with a special emphasis on alternative polyadenylation, microRNA and RNA binding proteins-mediated deadenylation, and discuss the implications of deregulation of these steps in DDR and human disease. This article is categorized under: RNA Processing > 3' End Processing RNA-Based Catalysis > Miscellaneous RNA-Catalyzed Reactions RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Michael Robert Murphy
- Department of Chemistry, Hunter College and Biochemistry Program, The Graduate Center, City University of New York, New York, New York
| | - Frida Esther Kleiman
- Department of Chemistry, Hunter College and Biochemistry Program, The Graduate Center, City University of New York, New York, New York
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10
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Nazarov IB, Bakhmet EI, Tomilin AN. KH-Domain Poly(C)-Binding Proteins as Versatile Regulators of Multiple Biological Processes. BIOCHEMISTRY (MOSCOW) 2019; 84:205-219. [PMID: 31221059 DOI: 10.1134/s0006297919030039] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Five known members of the family of KH-domain poly(C)-binding proteins (Pcbp1-4, hnRNP-K) have an unusually broad spectrum of cellular functions that include regulation of gene transcription, regulation of pre-mRNA processing, splicing, mRNA stability, translational silencing and enhancement, the control of iron turnover, and many others. Mechanistically, these proteins act via nucleic acid binding and protein-protein interactions. Through performing these multiple tasks, the KH-domain poly(C)-binding family members are involved in a wide variety of biological processes such as embryonic development, cell differentiation, and cancer. Deregulation of KH-domain protein expression is frequently associated with severe developmental defects and neoplasia. This review summarizes progress in studies of the KH-domain proteins made over past two decades. The review also reports our recent finding implying an involvement of the KH-factor Pcbp1 into control of transition from naïve to primed pluripotency cell state.
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Affiliation(s)
- I B Nazarov
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia.
| | - E I Bakhmet
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
| | - A N Tomilin
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
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11
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Multiphosphorylation and cellular localization of poly(rC) binding protein 1 during mitosis in hela cell. Biotechnol Lett 2019; 41:711-717. [PMID: 31076991 DOI: 10.1007/s10529-019-02679-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 04/24/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To monitor the phosphorylation modifications and cellular localization of poly(rC)-binding protein-1 (PCBP1) during the cell cycle progression of Hela cells. RESULT Hela cells highly synchronized at five different phases from interphase to mitosis were obtained. Using mitotic phosphoprotein-specific monoclonal antibody MPM-2, the exclusive occurrences of multiphosphorylation statuses of PCBP1 in mitosis were confirmed by a series of spots with increasing acidic pI (isoelectric point) in two rounds of 2D western blotting on the same membrane, and a visible molecular mass shift that can be eliminated by the treatment with λ phosphatase in 1D western blotting. Immnuofluorescence revealed the localization shift of PCBP1 during cell cycle, with accumulations in nucleus as a patch pattern in interphase, and a dispersive distribution without the area of the condensed chromosomes during mitosis. CONCLUSIONS These observations of mitosis-specific multiphosphorylations and localization shifts of PCBP1 suggest that the versatile PCBP1 was regulatable in a phosphorylation modification- and temporospatial-dependent manner in mitotic regulatory networks.
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12
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Masuda K, Kuwano Y. Diverse roles of RNA-binding proteins in cancer traits and their implications in gastrointestinal cancers. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 10:e1520. [PMID: 30479000 DOI: 10.1002/wrna.1520] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 02/06/2023]
Abstract
Gene expression patterns in cancer cells are strongly influenced by posttranscriptional mechanisms. RNA-binding proteins (RBPs) play key roles in posttranscriptional gene regulation; they can interact with target mRNAs in a sequence- and structure-dependent manner, and determine cellular behavior by manipulating the processing of these mRNAs. Numerous RBPs are aberrantly deregulated in many human cancers and hence, affect the functioning of mRNAs that encode proteins, implicated in carcinogenesis. Here, we summarize the key roles of RBPs in posttranscriptional gene regulation, describe RBPs disrupted in cancer, and lastly focus on RBPs that are responsible for implementing cancer traits in the digestive tract. These evidences may reveal a potential link between changes in expression/function of RBPs and malignant transformation, and a framework for new insights and potential therapeutic applications. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Kiyoshi Masuda
- Kawasaki Medical School at Kurashiki-City, Okayama, Japan
| | - Yuki Kuwano
- Department of Pathophysiology, Institute of Biomedical Sciences, Tokushima University Graduate School at Tokushima-City, Tokushima, Japan
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13
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Guo J, Jia R. Splicing factor poly(rC)-binding protein 1 is a novel and distinctive tumor suppressor. J Cell Physiol 2018; 234:33-41. [PMID: 30132844 DOI: 10.1002/jcp.26873] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/23/2018] [Indexed: 12/20/2022]
Abstract
A lot of evidence has been found on the link between tumorigenesis and the aberrant expression of splicing factors. A number of splicing factors have been reported to be either oncogenic or overexpressed in cancer cells. However, splicing factors can also play negative roles in tumorigenesis. In the current review, we focus on splicing factor poly(rC)-binding protein 1 (PCBP1), a novel tumor suppressor that is characterized by downregulation in many cancer types and shows inhibition of tumor formation and metastasis. Notably, the messenger RNA levels of PCBP1 are not significantly decreased in most cancer types. In fact, PCBP1 protein is often degraded or shows a loss-of-function through phosphorylation in cancer cells. PCBP1 is highly homologous to its family member, PCBP2. Interestingly, PCBP2 appears to be an oncogenic splicing factor. A growing body of evidence has shown that PCBP1 regulates alternative splicing, translation, and RNA stability of many cancer-related genes. Taking together, PCBP1 has distinctive tumor suppressive functions, and increasing PCBP1 expression may represent a new approach for cancer treatment.
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Affiliation(s)
- Jihua Guo
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Rong Jia
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan, China
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14
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Shi H, Li H, Yuan R, Guan W, Zhang X, Zhang S, Zhang W, Tong F, Li L, Song Z, Wang C, Yang S, Wang H. PCBP1 depletion promotes tumorigenesis through attenuation of p27 Kip1 mRNA stability and translation. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2018; 37:187. [PMID: 30086790 PMCID: PMC6081911 DOI: 10.1186/s13046-018-0840-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/10/2018] [Indexed: 11/10/2022]
Abstract
Background Poly C Binding Protein 1 (PCBP1) is an RNA-binding protein that binds and regulates translational activity of subsets of cellular mRNAs. Depletion of PCBP1 is implicated in various carcinomas, but the underlying mechanism in tumorigenesis remains elusive. Methods We performed a transcriptome-wide screen to identify novel bounding mRNA of PCBP1. The bind regions between PCBP1 with target mRNA were investigated by using point mutation and luciferase assay. Cell proliferation, cell cycle, tumorigenesis and cell apoptosis were also evaluated in ovary and colon cancer cell lines. The mechanism that PCBP1 affects p27 was analyzed by mRNA stability and ribosome profiling assays. We analyzed PCBP1 and p27 expression in ovary, colon and renal tumor samples and adjacent non-tumor tissues using RT-PCR, Western Blotting and immunohistochemistry. The prognostic significance of PCBP1 and p27 also analyzed using online databases. Results We identified cell cycle inhibitor p27Kip1 (p27) as a novel PCBP1-bound transcript. We then demonstrated that binding of PCBP1 to p27 3’UTR via its KH1 domain mainly stabilizes p27 mRNA, while enhances its translation to fuel p27 expression, prior to p27 protein degradation. The upregulated p27 consequently inhibits cell proliferation, cell cycle progression and tumorigenesis, whereas promotes cell apoptosis under paclitaxel treatment. Conversely, knockdown of PCBP1 in turn compromises p27 mRNA stability, leading to lower p27 level and tumorigenesis in vivo. Moreover, forced depletion of p27 counteracts the tumor suppressive ability of PCBP1 in the same PCBP1 over-expressing cells. Physiologically, we showed that decreases of both p27 mRNA and its protein expressions are well correlated to PCBP1 depletion in ovary, colon and renal tumor samples, independent of the p27 ubiquitin ligase Skp2 level. Correlation of PCBP1 with p27 is also found in the tamoxifen, doxorubincin and lapatinib resistant breast cancer cells of GEO database. Conclusion Our results thereby indicate that loss of PCBP1 expression firstly attenuates p27 expression at post-transcriptional level, and subsequently promotes carcinogenesis. PCBP1 could be used as a diagnostic marker to cancer patients. Electronic supplementary material The online version of this article (10.1186/s13046-018-0840-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hongshun Shi
- Centre for Translational Medicine, the First Affiliated Hospital, SUN Yat-sen University, 58 Second Zhongshan Road, Guangzhou, 510080, China.,Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Hui Li
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China.,Center for Stem Cell Biology and Tissue Engineering, Key laboratory of ministry of education, Sun Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Ronghua Yuan
- Department of General Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, Nantong, 226001, China
| | - Wen Guan
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Xiaomei Zhang
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Shaoyang Zhang
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Wenliang Zhang
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Fang Tong
- Centre for Translational Medicine, the First Affiliated Hospital, SUN Yat-sen University, 58 Second Zhongshan Road, Guangzhou, 510080, China.,Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Li Li
- Centre for Translational Medicine, the First Affiliated Hospital, SUN Yat-sen University, 58 Second Zhongshan Road, Guangzhou, 510080, China.,Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Zhihong Song
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Changwei Wang
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Shulan Yang
- Centre for Translational Medicine, the First Affiliated Hospital, SUN Yat-sen University, 58 Second Zhongshan Road, Guangzhou, 510080, China.
| | - Haihe Wang
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China. .,Center for Stem Cell Biology and Tissue Engineering, Key laboratory of ministry of education, Sun Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China.
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15
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Ji X, Humenik J, Yang D, Liebhaber SA. PolyC-binding proteins enhance expression of the CDK2 cell cycle regulatory protein via alternative splicing. Nucleic Acids Res 2018; 46:2030-2044. [PMID: 29253178 PMCID: PMC5829739 DOI: 10.1093/nar/gkx1255] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 12/01/2017] [Accepted: 12/05/2017] [Indexed: 11/13/2022] Open
Abstract
The PolyC binding proteins (PCBPs) impact alternative splicing of a subset of mammalian genes that are enriched in basic cellular functions. Here, we focus our analysis on PCBP-controlled cassette exon-splicing within the cell cycle control regulator cyclin-dependent kinase-2 (CDK2) transcript. We demonstrate that PCBP binding to a C-rich polypyrimidine tract (PPT) preceding exon 5 of the CDK2 transcript enhances cassette exon inclusion. This splice enhancement is U2AF65-independent and predominantly reflects actions of the PCBP1 isoform. Remarkably, PCBPs' control of CDK2 ex5 splicing has evolved subsequent to mammalian divergence via conversion of constitutive exon 5 inclusion in the mouse CDK2 transcript to PCBP-responsive exon 5 alternative splicing in humans. Importantly, exclusion of exon 5 from the hCDK2 transcript dramatically represses the expression of CDK2 protein with a corresponding perturbation in cell cycle kinetics. These data highlight a recently evolved post-transcriptional pathway in primate species with the potential to modulate cell cycle control.
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Affiliation(s)
- Xinjun Ji
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jesse Humenik
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Daphne Yang
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stephen A Liebhaber
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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16
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Espinoza-Lewis RA, Yang Q, Liu J, Huang ZP, Hu X, Chen D, Wang DZ. Poly(C)-binding protein 1 (Pcbp1) regulates skeletal muscle differentiation by modulating microRNA processing in myoblasts. J Biol Chem 2017; 292:9540-9550. [PMID: 28381556 DOI: 10.1074/jbc.m116.773671] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/04/2017] [Indexed: 11/06/2022] Open
Abstract
Regulation of gene expression during muscle development and disease remains incompletely understood. microRNAs are a class of small non-coding RNAs that regulate gene expression and function post-transcriptionally. The poly(C)-binding protein1 (Pcbp1, hnRNP-E1, or αCP-1) is an RNA-binding protein that has been reported to bind the 3'-UTRs of target genes to regulate mRNA stability and protein translation. However, Pcbp1's biological function and the general mechanism of action remain largely undetermined. Here, we report that Pcbp1 is a component of the miRNA-processing pathway that regulates miRNA biogenesis. siRNA-based inhibition of Pcbp1 in mouse skeletal muscle myoblasts led to dysregulated cellular proliferation and differentiation. We also found that Pcbp1 null mutant mice exhibit early embryonic lethality, indicating that Pcbp1 is indispensable for embryonic development. Interestingly, hypomorphic Pcbp1 mutant mice displayed defects in muscle growth due to defects in the proliferation and differentiation of myoblasts and muscle satellite cells, in addition to a slow to fast myofibril switch. Moreover, Pcbp1 modulated the processing of muscle-enriched miR-1, miR-133, and miR-206 by physically interacting with argonaute 2 (AGO2) and other miRNA pathway components. Our study, therefore, uncovers the important function of Pcbp1 in skeletal muscle and the microRNA pathway, signifying its potential as a therapeutic target for muscle disease.
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Affiliation(s)
- Ramón A Espinoza-Lewis
- From the Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Qiumei Yang
- From the Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115 and.,Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 6111130, China
| | - Jianming Liu
- From the Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Zhan-Peng Huang
- From the Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Xiaoyun Hu
- From the Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Daiwen Chen
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 6111130, China
| | - Da-Zhi Wang
- From the Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115 and
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17
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Mayanil CSK. That Which Is Bad Can Trigger Good in the Human Body-Homocysteine-Bound hnRNP-E1 as a Molecular Sensor of Physiologic Folate Deficiency. J Nutr 2017; 147:471-472. [PMID: 28250193 DOI: 10.3945/jn.117.247924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 02/03/2017] [Accepted: 02/03/2017] [Indexed: 11/14/2022] Open
Affiliation(s)
- Chandra Shekhar K Mayanil
- Department of Pediatric Neurosurgery, Ann and Robert H Lurie Children's Hospital of Chicago Research Center and Northwestern University Feinberg School of Medicine, Chicago, IL
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18
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Tang YS, Khan RA, Xiao S, Hansen DK, Stabler SP, Kusumanchi P, Jayaram HN, Antony AC. Evidence Favoring a Positive Feedback Loop for Physiologic Auto Upregulation of hnRNP-E1 during Prolonged Folate Deficiency in Human Placental Cells. J Nutr 2017; 147:482-498. [PMID: 28250194 PMCID: PMC5368577 DOI: 10.3945/jn.116.241364] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/07/2016] [Accepted: 01/11/2017] [Indexed: 12/27/2022] Open
Abstract
Background: Previously, we determined that heterogeneous nuclear ribonucleoprotein E1 (hnRNP-E1) functions as an intracellular physiologic sensor of folate deficiency. In this model, l-homocysteine, which accumulates intracellularly in proportion to the extent of folate deficiency, covalently binds to and thereby activates homocysteinylated hnRNP-E1 to interact with folate receptor-α mRNA; this high-affinity interaction triggers the translational upregulation of cell surface folate receptors, which enables cells to optimize folate uptake from the external milieu. However, integral to this model is the need for ongoing generation of hnRNP-E1 to replenish homocysteinylated hnRNP-E1 that is degraded.Objective: We searched for an interrelated physiologic mechanism that could also maintain the steady-state concentration of hnRNP-E1 during prolonged folate deficiency.Methods: A novel RNA-protein interaction was functionally characterized by using molecular and biochemical approaches in vitro and in vivo.Results: l-homocysteine triggered a dose-dependent high-affinity interaction between hnRNP-E1 and a 25-nucleotide cis element within the 5'-untranslated region of hnRNP-E1 mRNA; this led to a proportionate increase in these RNA-protein complexes, and translation of hnRNP-E1 both in vitro and within placental cells. Targeted perturbation of this RNA-protein interaction either by specific 25-nucleotide antisense oligonucleotides or mutation within this cis element or by small interfering RNA to hnRNP-E1 mRNA significantly reduced cellular biosynthesis of hnRNP-E1. Conversely, transfection of hnRNP-E1 mutant proteins that mimicked homocysteinylated hnRNP-E1 stimulated both cellular hnRNP-E1 and folate receptor biosynthesis. In addition, ferrous sulfate heptahydrate [iron(II)], which also binds hnRNP-E1, significantly perturbed this l-homocysteine-triggered RNA-protein interaction in a dose-dependent manner. Finally, folate deficiency induced dual upregulation of hnRNP-E1 and folate receptors in cultured human cells and tumor xenografts, and more selectively in various fetal tissues of folate-deficient dams.Conclusions: This novel positive feedback loop amplifies hnRNP-E1 during prolonged folate deficiency and thereby maximizes upregulation of folate receptors in order to restore folate homeostasis toward normalcy in placental cells. It will also functionally impact several other mRNAs of the nutrition-sensitive, folate-responsive posttranscriptional RNA operon that is orchestrated by homocysteinylated hnRNP-E1.
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Affiliation(s)
- Ying-Sheng Tang
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
| | - Rehana A Khan
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
| | - Suhong Xiao
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
| | | | - Sally P Stabler
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO; and
| | - Praveen Kusumanchi
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
| | | | - Aśok C Antony
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN; .,Richard L Roudebush Veterans Affairs Medical Center, Indianapolis, IN
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19
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Abstract
Since its discovery more than three decades ago, tumor suppressor p53 has been shown to play pivotal roles in both maintaining genomic integrity and tumor suppression. p53 functions as a transcription factor responding to a multitude of cellular stressors, regulating the transcription of many genes involved in cell-cycle arrest, senescence, autophagy, and apoptosis. Extensive work has revealed that p53 is one of the most commonly mutated tumor suppressor genes. The last three decades have demonstrated that p53 activity is controlled through transcriptional regulation and posttranslational modifications. However, evolving work is now uncovering that p53, and other p53 family members, are post-transcriptionally regulated by multiple RNA-binding proteins (RBPs). Understanding the regulation of p53 by RBPs may potentially open up the possibility for cancer therapeutic intervention. This review focuses on the posttranscriptional regulation of p53, and p53 family members, by RNA binding proteins and the reciprocal feedback pathways between several RNA-biding proteins modulating p53, and p53 family members.
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Affiliation(s)
- Chris Lucchesi
- Comparative Oncology Laboratory, School of Veterinary Medicine, School of Medicine, University of California at Davis, Davis, California 95616, USA
| | - Jin Zhang
- Comparative Oncology Laboratory, School of Veterinary Medicine, School of Medicine, University of California at Davis, Davis, California 95616, USA
| | - Xinbin Chen
- Comparative Oncology Laboratory, School of Veterinary Medicine, School of Medicine, University of California at Davis, Davis, California 95616, USA
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20
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Geuens T, Bouhy D, Timmerman V. The hnRNP family: insights into their role in health and disease. Hum Genet 2016; 135:851-67. [PMID: 27215579 PMCID: PMC4947485 DOI: 10.1007/s00439-016-1683-5] [Citation(s) in RCA: 655] [Impact Index Per Article: 81.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/09/2016] [Indexed: 12/14/2022]
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) represent a large family of RNA-binding proteins (RBPs) that contribute to multiple aspects of nucleic acid metabolism including alternative splicing, mRNA stabilization, and transcriptional and translational regulation. Many hnRNPs share general features, but differ in domain composition and functional properties. This review will discuss the current knowledge about the different hnRNP family members, focusing on their structural and functional divergence. Additionally, we will highlight their involvement in neurodegenerative diseases and cancer, and the potential to develop RNA-based therapies.
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Affiliation(s)
- Thomas Geuens
- Peripheral Neuropathy Group, VIB Molecular Genetics Department, University of Antwerp-CDE, Parking P4, Building V, Room 1.30, Universiteitsplein 1, 2610, Antwerp, Belgium
- Neurogenetics Laboratory, Institute Born Bunge, University of Antwerp, Antwerp, Belgium
| | - Delphine Bouhy
- Peripheral Neuropathy Group, VIB Molecular Genetics Department, University of Antwerp-CDE, Parking P4, Building V, Room 1.30, Universiteitsplein 1, 2610, Antwerp, Belgium
- Neurogenetics Laboratory, Institute Born Bunge, University of Antwerp, Antwerp, Belgium
| | - Vincent Timmerman
- Peripheral Neuropathy Group, VIB Molecular Genetics Department, University of Antwerp-CDE, Parking P4, Building V, Room 1.30, Universiteitsplein 1, 2610, Antwerp, Belgium.
- Neurogenetics Laboratory, Institute Born Bunge, University of Antwerp, Antwerp, Belgium.
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21
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Ren C, Zhang J, Yan W, Zhang Y, Chen X. RNA-binding Protein PCBP2 Regulates p73 Expression and p73-dependent Antioxidant Defense. J Biol Chem 2016; 291:9629-37. [PMID: 26907686 DOI: 10.1074/jbc.m115.712125] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Indexed: 11/06/2022] Open
Abstract
TAp73, a member of the p53 family tumor suppressors, plays a critical rule in tumor suppression and neuronal development. However, how p73 activity is controlled at the posttranscriptional level is not well understood. Here, we showed that TAp73 activity is regulated by RNA-binding protein PCBP2. Specifically, we found that knockdown or knock-out of PCBP2 reduces, whereas ectopic expression of PCBP2 increases, TAp73 expression. We also showed that PCBP2 is necessary for p73 mRNA stability via the CU-rich elements in p73 3'-UTR. To uncover the biological relevance of PCBP2-regulated TAp73 expression, we showed that ectopic expression of PCBP2 inhibits, whereas knockdown or knock-out of PCBP2 increases, the production of reactive oxygen species (ROS) in a TAp73-dependent manner. Additionally, we found that glutaminase 2 (GLS2), a modulator of p73-dependent antioxidant defense, is also involved in PCBP2-regulated ROS production. Moreover, we generated PCBP2-deficient mice and primary mouse embryonic fibroblasts (MEFs) and showed that loss of PCBP2 leads to decreased p73 expression and, subsequently, increased ROS production and accelerated cellular senescence. Together, our data suggest that PCBP2 regulates p73 expression via mRNA stability and p73-dependent biological function in ROS production and cellular senescence.
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Affiliation(s)
- Cong Ren
- From the Comparative Oncology Laboratory, Schools of Medicine and Veterinary Medicine, University of California, Davis, California 95616
| | - Jin Zhang
- From the Comparative Oncology Laboratory, Schools of Medicine and Veterinary Medicine, University of California, Davis, California 95616
| | - Wensheng Yan
- From the Comparative Oncology Laboratory, Schools of Medicine and Veterinary Medicine, University of California, Davis, California 95616
| | - Yanhong Zhang
- From the Comparative Oncology Laboratory, Schools of Medicine and Veterinary Medicine, University of California, Davis, California 95616
| | - Xinbin Chen
- From the Comparative Oncology Laboratory, Schools of Medicine and Veterinary Medicine, University of California, Davis, California 95616
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22
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Ji X, Park JW, Bahrami-Samani E, Lin L, Duncan-Lewis C, Pherribo G, Xing Y, Liebhaber SA. αCP binding to a cytosine-rich subset of polypyrimidine tracts drives a novel pathway of cassette exon splicing in the mammalian transcriptome. Nucleic Acids Res 2016; 44:2283-97. [PMID: 26896798 PMCID: PMC4797308 DOI: 10.1093/nar/gkw088] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 02/03/2016] [Indexed: 12/17/2022] Open
Abstract
Alternative splicing (AS) is a robust generator of mammalian transcriptome complexity. Splice site specification is controlled by interactions of cis-acting determinants on a transcript with specific RNA binding proteins. These interactions are frequently localized to the intronic U-rich polypyrimidine tracts (PPT) located 5′ to the majority of splice acceptor junctions. αCPs (also referred to as polyC-binding proteins (PCBPs) and hnRNPEs) comprise a subset of KH-domain proteins with high affinity and specificity for C-rich polypyrimidine motifs. Here, we demonstrate that αCPs promote the splicing of a defined subset of cassette exons via binding to a C-rich subset of polypyrimidine tracts located 5′ to the αCP-enhanced exonic segments. This enhancement of splice acceptor activity is linked to interactions of αCPs with the U2 snRNP complex and may be mediated by cooperative interactions with the canonical polypyrimidine tract binding protein, U2AF65. Analysis of αCP-targeted exons predicts a substantial impact on fundamental cell functions. These findings lead us to conclude that the αCPs play a direct and global role in modulating the splicing activity and inclusion of an array of cassette exons, thus driving a novel pathway of splice site regulation within the mammalian transcriptome.
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Affiliation(s)
- Xinjun Ji
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Juw Won Park
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA Department of Computer Engineering and Computer Science, University of Louisville, Louisville, KY 40292, USA KBRIN Bioinformatics Core, University of Louisville, Louisville, KY 40202, USA
| | - Emad Bahrami-Samani
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Lan Lin
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Christopher Duncan-Lewis
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gordon Pherribo
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yi Xing
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Stephen A Liebhaber
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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23
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Ye F, Xin Z, Han W, Fan J, Yin B, Wu S, Yang W, Yuan J, Qiang B, Sun W, Peng X. Quantitative Proteomics Analysis of the Hepatitis C Virus Replicon High-Permissive and Low-Permissive Cell Lines. PLoS One 2015; 10:e0142082. [PMID: 26544179 PMCID: PMC4636247 DOI: 10.1371/journal.pone.0142082] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 10/16/2015] [Indexed: 01/16/2023] Open
Abstract
Chronic hepatitis C virus (HCV) infection is one of the leading causes of severe hepatitis. The molecular mechanisms underlying HCV replication and pathogenesis remain unclear. The development of the subgenome replicon model system significantly enhanced study of HCV. However, the permissiveness of the HCV subgenome replicon greatly differs among different hepatoma cell lines. Proteomic analysis of different permissive cell lines might provide new clues in understanding HCV replication. In this study, to detect potential candidates that might account for the differences in HCV replication. Label-free and iTRAQ labeling were used to analyze the differentially expressed protein profiles between Huh7.5.1 wt and HepG2 cells. A total of 4919 proteins were quantified in which 114 proteins were commonly identified as differentially expressed by both quantitative methods. A total of 37 differential proteins were validated by qRT-PCR. The differential expression of Glutathione S-transferase P (GSTP1), Ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCHL1), carboxylesterase 1 (CES1), vimentin, Proteasome activator complex subunit1 (PSME1), and Cathepsin B (CTSB) were verified by western blot. And over-expression of CTSB or knock-down of vimentin induced significant changes to HCV RNA levels. Additionally, we demonstrated that CTSB was able to inhibit HCV replication and viral protein translation. These results highlight the potential role of CTSB and vimentin in virus replication.
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Affiliation(s)
- Fei Ye
- The State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zhongshuai Xin
- Division of Hormone, National Institute for Food and Drug Control, Beijing, China
| | - Wei Han
- The State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jingjing Fan
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Bin Yin
- The State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shuzhen Wu
- Core facility of instrument, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wei Yang
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jiangang Yuan
- The State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Boqin Qiang
- The State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wei Sun
- Core facility of instrument, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- * E-mail: (XP); (WS)
| | - Xiaozhong Peng
- The State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- * E-mail: (XP); (WS)
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The Poly(C) Binding Protein Pcbp2 and Its Retrotransposed Derivative Pcbp1 Are Independently Essential to Mouse Development. Mol Cell Biol 2015; 36:304-19. [PMID: 26527618 DOI: 10.1128/mcb.00936-15] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 10/28/2015] [Indexed: 12/12/2022] Open
Abstract
RNA-binding proteins participate in a complex array of posttranscriptional controls essential to cell type specification and somatic development. Despite their detailed biochemical characterizations, the degree to which each RNA-binding protein impacts mammalian embryonic development remains incompletely defined, and the level of functional redundancy among subsets of these proteins remains open to question. The poly(C) binding proteins, PCBPs (αCPs and hnRNP E proteins), are encoded by a highly conserved and broadly expressed gene family. The two major Pcbp isoforms, Pcbp2 and Pcbp1, are robustly expressed in a wide range of tissues and exert both nuclear and cytoplasmic controls over gene expression. Here, we report that Pcbp1-null embryos are rendered nonviable in the peri-implantation stage. In contrast, Pcbp2-null embryos undergo normal development until midgestation (12.5 to 13.5 days postcoitum), at which time they undergo a dramatic loss in viability associated with combined cardiovascular and hematopoietic abnormalities. Mice heterozygous for either Pcbp1 or Pcbp2 null alleles display a mild and nondisruptive defect in initial postpartum weight gain. These data reveal that Pcbp1 and Pcbp2 are individually essential for mouse embryonic development and have distinct impacts on embryonic viability and that Pcpb2 has a nonredundant in vivo role in hematopoiesis. These data further provide direct evidence that Pcbp1, a retrotransposed derivative of Pcpb2, has evolved an essential function(s) in the mammalian genome.
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25
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Tang SL, Gao YL, Chen XB. MicroRNA-214 targets PCBP2 to suppress the proliferation and growth of glioma cells. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:12571-12576. [PMID: 26722446 PMCID: PMC4680391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 06/20/2015] [Indexed: 06/05/2023]
Abstract
PCBP2, a member of the poly(C)-binding protein (PCBP) family, is involved in posttranscriptional and translational regulation by interacting with single-stranded poly(C) motifs in target mRNAs. Recent studies have shown that PCBP2 is overexpressed and plays an important role in human cancers, including glioma. However, the molecular basis for its up-regulation remains poorly understood. Here, we show that microRNA-214 (miR-214) interacts with the 3'-untranslated region of PCBP2 mRNA and induces its degradation, leading to reductions in its protein expression. As a result, overexpression of miR-214 mimics significantly inhibited, while its antisense oligos proliferation and growth of glioma cells. Restoration of PCBP2 remarkably reversed the tumor-suppressive effects of miR-214 on cell proliferation and growth. In summary, our data indicate that miR-214 may function as tumor suppressor in glioma by targeting PCBP2.
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Affiliation(s)
- Shi-Lei Tang
- Department of Neurosurgery, Huaihe Hospital, Henan UniversityKaifeng 475000, China
| | - Yuan-Lin Gao
- Department of Neurology, Kaifeng Central HospitalKaifeng 475000, China
| | - Xiao-Bing Chen
- Department of Neurosurgery, Huaihe Hospital, Henan UniversityKaifeng 475000, China
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26
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Xia N, Tang Z, Wang C, Xu G, Nie X, Zhang W, Zhao Y, Wang S, Zhu X, Cui S. PCBP2 regulates hepatic insulin sensitivity via HIF-1α and STAT3 pathway in HepG2 cells. Biochem Biophys Res Commun 2015; 463:116-22. [DOI: 10.1016/j.bbrc.2015.04.150] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Accepted: 04/30/2015] [Indexed: 10/23/2022]
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Gelfand BD, Wright CB, Kim Y, Yasuma T, Yasuma R, Li S, Fowler BJ, Bastos-Carvalho A, Kerur N, Uittenbogaard A, Han YS, Lou D, Kleinman ME, McDonald WH, Núñez G, Georgel P, Dunaief JL, Ambati J. Iron Toxicity in the Retina Requires Alu RNA and the NLRP3 Inflammasome. Cell Rep 2015; 11:1686-93. [PMID: 26074074 DOI: 10.1016/j.celrep.2015.05.023] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/23/2015] [Accepted: 05/08/2015] [Indexed: 12/16/2022] Open
Abstract
Excess iron induces tissue damage and is implicated in age-related macular degeneration (AMD). Iron toxicity is widely attributed to hydroxyl radical formation through Fenton's reaction. We report that excess iron, but not other Fenton catalytic metals, induces activation of the NLRP3 inflammasome, a pathway also implicated in AMD. Additionally, iron-induced degeneration of the retinal pigmented epithelium (RPE) is suppressed in mice lacking inflammasome components caspase-1/11 or Nlrp3 or by inhibition of caspase-1. Iron overload increases abundance of RNAs transcribed from short interspersed nuclear elements (SINEs): Alu RNAs and the rodent equivalent B1 and B2 RNAs, which are inflammasome agonists. Targeting Alu or B2 RNA prevents iron-induced inflammasome activation and RPE degeneration. Iron-induced SINE RNA accumulation is due to suppression of DICER1 via sequestration of the co-factor poly(C)-binding protein 2 (PCBP2). These findings reveal an unexpected mechanism of iron toxicity, with implications for AMD and neurodegenerative diseases associated with excess iron.
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Affiliation(s)
- Bradley D Gelfand
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA; Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40536, USA; Department of Microbiology, Immunology, and Human Genetics, University of Kentucky, Lexington, KY 40536, USA.
| | - Charles B Wright
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Younghee Kim
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Tetsuhiro Yasuma
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Reo Yasuma
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Shengjian Li
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Benjamin J Fowler
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA; Department of Physiology, University of Kentucky, Lexington, KY 40536, USA
| | - Ana Bastos-Carvalho
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Nagaraj Kerur
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Annette Uittenbogaard
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Youn Seon Han
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Dingyuan Lou
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Mark E Kleinman
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - W Hayes McDonald
- Proteomics Laboratory, Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37205, USA
| | - Gabriel Núñez
- Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Philippe Georgel
- INSERM UMR_S 1109, Fédération de Médecine Translationnelle (FMTS), Université de Strasbourg, Strasbourg 67085, France
| | - Joshua L Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jayakrishna Ambati
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA; Department of Physiology, University of Kentucky, Lexington, KY 40536, USA
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Abstract
POLH (DNA polymerase η), a target of p53 tumour suppressor, plays a key role in TLS (translesion DNA synthesis). Loss of POLH is responsible for the human cancer-prone syndrome XPV (xeroderma pigmentosum variant). Owing to its critical role in DNA repair and genome stability, POLH expression and activity are regulated by multiple pathways. In the present study, we found that the levels of both POLH transcript and protein were decreased upon knockdown of the transcript encoding PCBP1 [poly(rC)-binding protein 1]. We also found that the half-life of POLH mRNA was markedly decreased upon knockdown of PCBP1. Moreover, we found that PCBP1 directly bound to the POLH 3'-UTR and the PCBP1-binding site in POLH mRNA is an atypical AU-rich element. Finally, we showed that the AU-rich element in POLH 3'-UTR was responsive to PCBP1 and sufficient for PCBP1 to regulate POLH expression. Taken together, we uncovered a novel mechanism by which POLH expression is controlled by PCBP1 via mRNA stability.
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Zhang LN, Yan YB. Depletion of poly(A)-specific ribonuclease (PARN) inhibits proliferation of human gastric cancer cells by blocking cell cycle progression. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:522-34. [PMID: 25499764 DOI: 10.1016/j.bbamcr.2014.12.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 12/20/2022]
Abstract
Regulation of mRNA decay plays a crucial role in the post-transcriptional control of cell growth, survival, differentiation, death and senescence. Deadenylation is a rate-limiting step in the silence and degradation of the bulk of highly regulated mRNAs. However, the physiological functions of various deadenylases have not been fully deciphered. In this research, we found that poly(A)-specific ribonuclease (PARN) was upregulated in gastric tumor tissues and gastric cancer cell lines MKN28 and AGS. The cellular function of PARN was investigated by stably knocking down the endogenous PARN in the MKN28 and AGS cells. Our results showed that PARN-depletion significantly inhibited the proliferation of the two types of gastric cancer cells and promoted cell death, but did not significantly affect cell motility and invasion. The depletion of PARN arrested the gastric cancer cells at the G0/G1 phase by upregulating the expression levels of p53 and p21 but not p27. The mRNA stability of p53 was unaffected by PARN-knockdown in both types of cells. A significant stabilizing effect of PARN-depletion on p21 mRNA was observed in the AGS cells but not in the MKN28 cells. We further showed that the p21 3'-UTR triggered the action of PARN in the AGS cells. The dissimilar observations between the MKN28 and AGS cells as well as various stress conditions suggested that the action of PARN strongly relied on protein expression profiles of the cells, which led to heterogeneity in the stability of PARN-targeted mRNAs.
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Affiliation(s)
- Li-Na Zhang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yong-Bin Yan
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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Specific enrichment of the RNA-binding proteins PCBP1 and PCBP2 in chief cells of the murine gastric mucosa. Gene Expr Patterns 2014; 14:78-87. [PMID: 24480778 DOI: 10.1016/j.gep.2014.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 12/31/2013] [Accepted: 01/20/2014] [Indexed: 01/05/2023]
Abstract
RNA-binding proteins and corresponding post-transcriptional controls play critical roles in gene expression. The poly-(C) binding proteins, PCBPs (αCPs, hnRNPEs), comprise a well-characterized family of abundant RNA-binding proteins that impact on RNA processing in the nucleus as well as mRNA stability and translation in the cytoplasm. Here we demonstrate that PCBP1 and PCBP2 are abundantly expressed in the gastric epithelium with prominent enrichment in specific cell types within the gastric glandular mucosa. The spatial and intracellular patterns of PCBP1 and PCBP2 expression in these regions are highly correlated. Remarkably, we observe that these proteins are present in the nuclear and cytoplasmic compartments of zymogenic chief cells while they are restricted to the nuclear compartment in acid-secreting parietal cells and poorly expressed in pit cells that line the gland exit. This specificity of expression patterns and subcellular localization of PCBP1 and PCBP2, along with their appearance in the precursor tissues of the gastric epithelium during early postnatal development, suggests these RNA-binding proteins play specific roles in cell differentiation and organismal development within the gastric glandular epithelium.
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Jiang Y, Zhang M, Qian Y, Xu E, Zhang J, Chen X. Rbm24, an RNA-binding protein and a target of p53, regulates p21 expression via mRNA stability. J Biol Chem 2013; 289:3164-75. [PMID: 24356969 DOI: 10.1074/jbc.m113.524413] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
p21, a cyclin-dependent kinase inhibitor, is necessary for proper control of the cell cycle and premature senescence. Thus, p21 expression needs to be tightly controlled. In this study, we found that Rbm24, an RNA-binding protein and a target gene of the p53 protein, can regulate p21 expression via mRNA stability. Specifically, we showed that Rbm24 is induced by DNA damage and Mdm2 inhibitor Nutlin-3. We also found that p53 protein binds to and activates the promoter of the Rbm24 gene. Moreover, we found that overexpression of Rbm24 increases, whereas knockdown of Rbm24 decreases, p21 mRNA and protein expression. In addition, we demonstrated that overexpression of Rbm24 enhances the half-life of p21 transcript. Consistent with this, we provided evidence that Rbm24 binds to the 3'-untranslated region (3'-UTR) of p21 transcript and an AU/U-rich element in the p21 3'-UTR is necessary for Rbm24 to increase p21 expression. Finally, we showed that the RNA recognition motif in Rbm24 is required for binding to p21 transcript and subsequently for inducing p21 expression. Altogether, we uncovered that Rbm24 is a novel player in the p53 pathway, which may be explored to restore proper cell cycle control in p53-deficient tumors via p21.
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Affiliation(s)
- Yuqian Jiang
- From the Comparative Oncology Laboratory, University of California, Davis, California 95616
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32
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Poly (C)-binding protein 1 regulates p63 expression through mRNA stability. PLoS One 2013; 8:e71724. [PMID: 23940783 PMCID: PMC3737132 DOI: 10.1371/journal.pone.0071724] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 07/09/2013] [Indexed: 11/19/2022] Open
Abstract
p63, a transcription factor and p53 family protein, plays a crucial role in tumor suppression and development of various epithelial tissues. While p63 expression is controlled mostly by post-translational modifications, recent studies indicate that transcriptional and posttranscriptional regulations are essential for proper p63 expression. Here, we investigated the regulation of p63 expression by poly (C)-binding protein 1 (PCBP1, also known as hnRNP-E1 and αCP1). We found that knockdown of PCBP1 decreases the level of p63 transcript and protein. We also found that PCBP1 regulates the stability of p63 mRNA via binding to p63 3’UTR. Additionally, we found that a CU-rich element (CUE) in p63 3′UTR is bound by and responsive to PCBP1. Together, we conclude that PCBP1 regulates p63 expression via mRNA stability.
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Montecucco A, Biamonti G. Pre-mRNA processing factors meet the DNA damage response. Front Genet 2013; 4:102. [PMID: 23761808 PMCID: PMC3674313 DOI: 10.3389/fgene.2013.00102] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 05/20/2013] [Indexed: 12/04/2022] Open
Abstract
It is well-known that DNA-damaging agents induce genome instability, but only recently have we begun to appreciate that chromosomes are fragile per se and frequently subject to DNA breakage. DNA replication further magnifies such fragility, because it leads to accumulation of single-stranded DNA. Recent findings suggest that chromosome fragility is similarly increased during transcription. Transcripts produced by RNA polymerase II (RNAPII) are subject to multiple processing steps, including maturation of 5′ and 3′ ends and splicing, followed by transport to the cytoplasm. RNA maturation starts on nascent transcripts and is mediated by a number of diverse proteins and ribonucleoprotein particles some of which are recruited cotranscriptionally through interactions with the carboxy-terminal domain of RNAPII. This coupling is thought to maximize efficiency of pre-mRNA maturation and directly impacts the choice of alternative splice sites. Mounting evidence suggests that lack of coordination among different RNA maturation steps, by perturbing the interaction of nascent transcripts with the DNA template, has deleterious effects on genome stability. Thus, in the absence of proper surveillance mechanisms, transcription could be a major source of DNA damage in cancer. Recent high-throughput screenings in human cells and budding yeast have identified several factors implicated in RNA metabolism that are targets of DNA damage checkpoint kinases: ATM (ataxia telangiectasia mutated) and ATR (ATM-Rad3 related) (Tel1 and Mec1 in budding yeast, respectively). Moreover, inactivation of various RNA processing factors induces accumulation of γH2AX foci, an early sign of DNA damage. Thus, a complex network is emerging that links DNA repair and RNA metabolism. In this review we provide a comprehensive overview of the role played by pre-mRNA processing factors in the cell response to DNA damage and in the maintenance of genome stability.
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Piazzi M, Blalock WL, Bavelloni A, Faenza I, D'Angelo A, Maraldi NM, Cocco L. Phosphoinositide-specific phospholipase C β 1b (PI-PLCβ1b) interactome: affinity purification-mass spectrometry analysis of PI-PLCβ1b with nuclear protein. Mol Cell Proteomics 2013; 12:2220-35. [PMID: 23665500 DOI: 10.1074/mcp.m113.029686] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two isoforms of inositide-dependent phospholipase C β1 (PI-PLCβ1) are generated by alternative splicing (PLCβ1a and PLCβ1b). Both isoforms are present within the nucleus, but in contrast to PLCβ1a, the vast majority of PLCβ1b is nuclear. In mouse erythroid leukemia cells, PI-PLCβ1 is involved in the regulation of cell division and the balance between cell proliferation and differentiation. It has been demonstrated that nuclear localization is crucial for the enzymatic function of PI-PLCβ1, although the mechanism by which this nuclear import occurs has never been fully characterized. The aim of this study was to characterize both the mechanism of nuclear localization and the molecular function of nuclear PI-PLCβ1 by identifying its interactome in Friend's erythroleukemia isolated nuclei, utilizing a procedure that coupled immuno-affinity purification with tandem mass spectrometry analysis. Using this procedure, 160 proteins were demonstrated to be in association with PI-PLCβ1b, some of which have been previously characterized, such as the splicing factor SRp20 (Srsf3) and Lamin B (Lmnb1). Co-immunoprecipitation analysis of selected proteins confirmed the data obtained via mass spectrometry. Of particular interest was the identification of the nuclear import proteins Kpna2, Kpna4, Kpnb1, Ran, and Rangap1, as well as factors involved in hematological malignancies and several anti-apoptotic proteins. These data give new insight into possible mechanisms of nuclear trafficking and functioning of this critical signaling molecule.
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Affiliation(s)
- Manuela Piazzi
- Cell Signaling Laboratory, Department of Biomedical Science DIBINEM, University of Bologna, 40126 Bologna, Italy
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Han W, Xin Z, Zhao Z, Bao W, Lin X, Yin B, Zhao J, Yuan J, Qiang B, Peng X. RNA-binding protein PCBP2 modulates glioma growth by regulating FHL3. J Clin Invest 2013; 123:2103-18. [PMID: 23585479 DOI: 10.1172/jci61820] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 02/07/2013] [Indexed: 02/01/2023] Open
Abstract
PCBP2 is a member of the poly(C)-binding protein (PCBP) family, which plays an important role in posttranscriptional and translational regulation by interacting with single-stranded poly(C) motifs in target mRNAs. Several PCBP family members have been reported to be involved in human malignancies. Here, we show that PCBP2 is upregulated in human glioma tissues and cell lines. Knockdown of PCBP2 inhibited glioma growth in vitro and in vivo through inhibition of cell-cycle progression and induction of caspase-3-mediated apoptosis. Thirty-five mRNAs were identified as putative PCBP2 targets/interactors using RIP-ChIP protein-RNA interaction arrays in a human glioma cell line, T98G. Four-and-a-half LIM domain 3 (FHL3) mRNA was downregulated in human gliomas and was identified as a PCBP2 target. Knockdown of PCBP2 enhanced the expression of FHL3 by stabilizing its mRNA. Overexpression of FHL3 attenuated cell growth and induced apoptosis. This study establishes a link between PCBP2 and FHL3 proteins and identifies a new pathway for regulating glioma progression.
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Affiliation(s)
- Wei Han
- State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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36
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Davidovic L, Durand N, Khalfallah O, Tabet R, Barbry P, Mari B, Sacconi S, Moine H, Bardoni B. A novel role for the RNA-binding protein FXR1P in myoblasts cell-cycle progression by modulating p21/Cdkn1a/Cip1/Waf1 mRNA stability. PLoS Genet 2013; 9:e1003367. [PMID: 23555284 PMCID: PMC3605292 DOI: 10.1371/journal.pgen.1003367] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 01/21/2013] [Indexed: 12/14/2022] Open
Abstract
The Fragile X-Related 1 gene (FXR1) is a paralog of the Fragile X Mental Retardation 1 gene (FMR1), whose absence causes the Fragile X syndrome, the most common form of inherited intellectual disability. FXR1P plays an important role in normal muscle development, and its absence causes muscular abnormalities in mice, frog, and zebrafish. Seven alternatively spliced FXR1 transcripts have been identified and two of them are skeletal muscle-specific. A reduction of these isoforms is found in myoblasts from Facio-Scapulo Humeral Dystrophy (FSHD) patients. FXR1P is an RNA–binding protein involved in translational control; however, so far, no mRNA target of FXR1P has been linked to the drastic muscular phenotypes caused by its absence. In this study, gene expression profiling of C2C12 myoblasts reveals that transcripts involved in cell cycle and muscular development pathways are modulated by Fxr1-depletion. We observed an increase of p21—a regulator of cell-cycle progression—in Fxr1-knocked-down mouse C2C12 and FSHD human myoblasts. Rescue of this molecular phenotype is possible by re-expressing human FXR1P in Fxr1-depleted C2C12 cells. FXR1P muscle-specific isoforms bind p21 mRNA via direct interaction with a conserved G-quadruplex located in its 3′ untranslated region. The FXR1P/G-quadruplex complex reduces the half-life of p21 mRNA. In the absence of FXR1P, the upregulation of p21 mRNA determines the elevated level of its protein product that affects cell-cycle progression inducing a premature cell-cycle exit and generating a pool of cells blocked at G0. Our study describes a novel role of FXR1P that has crucial implications for the understanding of its role during myogenesis and muscle development, since we show here that in its absence a reduced number of myoblasts will be available for muscle formation/regeneration, shedding new light into the pathophysiology of FSHD. Muscle development is a complex process controlled by the timely expression of genes encoding crucial regulators of the muscle cell precursors called myoblasts. We know from previous studies that inactivation of the Fragile X related 1 (FXR1) gene in various animal models (mouse, frog, and zebrafish) causes muscular and cardiac abnormalities. Also, FXR1P is reduced in a human myopathy called Fascio-Scapulo Humeral Dystrophy (FSHD), suggesting its critical role in muscle that findings presented in this study contribute to elucidating. Cell-cycle arrest is a prerequisite to differentiation of myoblasts into mature myotubes, which will form the muscle. One key regulator is the p21/Cdkn1a/Cip1/Waf1 protein, which commands myoblasts to stop proliferating, and this action is particularly important during muscle regeneration. In this study, we have identified FXR1P as a novel regulator of p21 expression. We show that FXR1P absence in mouse myoblasts and FSHD-derived myopathic myoblasts increases abnormally the levels of p21, causing a premature cell cycle exit of myoblasts. Our study predicts that FXR1P absence leads to a reduced number of myoblasts available for muscle formation and regeneration. This explains the drastic effects of FXR1 inactivation on muscle and brings a better understanding of the molecular/cellular bases of FSHD.
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Affiliation(s)
- Laetitia Davidovic
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR 7275, Valbonne, France
- Université de Nice-Sophia Antipolis, Nice, France
| | - Nelly Durand
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR 7275, Valbonne, France
- Université de Nice-Sophia Antipolis, Nice, France
| | - Olfa Khalfallah
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR 7275, Valbonne, France
- Université de Nice-Sophia Antipolis, Nice, France
| | - Ricardo Tabet
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), CNRS, UMR7104, Inserm U596, Collège de France, Strasbourg University, Illkirch-Graffenstaden, France
| | - Pascal Barbry
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR 7275, Valbonne, France
- Université de Nice-Sophia Antipolis, Nice, France
| | - Bernard Mari
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR 7275, Valbonne, France
- Université de Nice-Sophia Antipolis, Nice, France
| | - Sabrina Sacconi
- INSERM U638, Faculté de Médecine, Université de Nice Sophia-Antipolis, Centre de Référence pour les Maladies Neuromusculaires, CHU de Nice, Nice, France
| | - Hervé Moine
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), CNRS, UMR7104, Inserm U596, Collège de France, Strasbourg University, Illkirch-Graffenstaden, France
| | - Barbara Bardoni
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR 7275, Valbonne, France
- Université de Nice-Sophia Antipolis, Nice, France
- * E-mail:
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Ebrahimnezhad Darzi S, Amirghofran Z. Dichloromethane fraction of Melissa officinalis induces apoptosis by activation of intrinsic and extrinsic pathways in human leukemia cell lines. Immunopharmacol Immunotoxicol 2013; 35:313-20. [PMID: 23432355 DOI: 10.3109/08923973.2013.768268] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Various components from medicinal plants are currently used in cancer therapy because of their apoptosis-inducing effects. The present study has aimed to investigate the growth inhibitory and apoptotic effects of Melissa officinalis on tumor cells. We prepared different fractions of this plant to investigate their inhibitory effects on two leukemia cell lines, Jurkat and K562. Fractions with the highest inhibitory effects were examined for induction of apoptosis by the annexin V/propidium iodide assay and cell cycle changes by flow cytometry. Real-time polymerase chain reaction evaluated the changes in expression of apoptosis-related genes. Among different fractions, dichloromethane and n-hexane dose-dependent showed the strongest inhibitory effects on both K562 and Jurkat cells. The dichloromethane fraction significantly induced apoptosis at concentration of 50 µg/ml on Jurkat (85.66 ± 4.9%) and K562 cells (65.04 ± 0.93%) at 24 h after treatment (p < 0.002). According to cell cycle analysis, more than 70% of the cells accumulated in the sub-G1 phase when cultured in the presence of the dichloromethane fraction. This fraction up-regulated Fas and Bax mRNA expression as well as the Bax/Bcl-2 ratio according to cell type, showing its effect on the activation of both extrinsic and intrinsic pathways of apoptosis. The expression of apoptosis-related genes did not significantly change following treatment with the n-hexane fraction. These data indicated that the dichloromethane fraction of M. officinalis had the ability to induce apoptosis and change apoptosis-related gene expression in leukemia cells.
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Affiliation(s)
- Salimeh Ebrahimnezhad Darzi
- Department of Immunology, Medicinal and Natural Products Chemistry Research Center and Autoimmune Disease Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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38
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Singer S, Zhao R, Barsotti AM, Ouwehand A, Fazollahi M, Coutavas E, Breuhahn K, Neumann O, Longerich T, Pusterla T, Powers MA, Giles KM, Leedman PJ, Hess J, Grunwald D, Bussemaker HJ, Singer RH, Schirmacher P, Prives C. Nuclear pore component Nup98 is a potential tumor suppressor and regulates posttranscriptional expression of select p53 target genes. Mol Cell 2012; 48:799-810. [PMID: 23102701 PMCID: PMC3525737 DOI: 10.1016/j.molcel.2012.09.020] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 06/06/2012] [Accepted: 09/17/2012] [Indexed: 12/21/2022]
Abstract
The p53 tumor suppressor utilizes multiple mechanisms to selectively regulate its myriad target genes, which in turn mediate diverse cellular processes. Here, using conventional and single-molecule mRNA analyses, we demonstrate that the nucleoporin Nup98 is required for full expression of p21, a key effector of the p53 pathway, but not several other p53 target genes. Nup98 regulates p21 mRNA levels by a posttranscriptional mechanism in which a complex containing Nup98 and the p21 mRNA 3'UTR protects p21 mRNA from degradation by the exosome. An in silico approach revealed another p53 target (14-3-3σ) to be similarly regulated by Nup98. The expression of Nup98 is reduced in murine and human hepatocellular carcinomas (HCCs) and correlates with p21 expression in HCC patients. Our study elucidates a previously unrecognized function of wild-type Nup98 in regulating select p53 target genes that is distinct from the well-characterized oncogenic properties of Nup98 fusion proteins.
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MESH Headings
- 14-3-3 Proteins/genetics
- 14-3-3 Proteins/metabolism
- 3' Untranslated Regions
- ATP Binding Cassette Transporter, Subfamily B/genetics
- ATP Binding Cassette Transporter, Subfamily B/metabolism
- Animals
- Antineoplastic Agents, Phytogenic/pharmacology
- Apoptosis/drug effects
- Binding Sites
- Camptothecin/pharmacology
- Carcinoma, Hepatocellular/genetics
- Carcinoma, Hepatocellular/metabolism
- Carcinoma, Hepatocellular/pathology
- Cellular Senescence
- Cyclin-Dependent Kinase Inhibitor p21/genetics
- Cyclin-Dependent Kinase Inhibitor p21/metabolism
- Exosomes/metabolism
- Gene Expression Regulation, Neoplastic
- Hep G2 Cells
- Humans
- Liver Neoplasms/genetics
- Liver Neoplasms/metabolism
- Liver Neoplasms/pathology
- Male
- Mice
- Mice, Knockout
- Nuclear Pore Complex Proteins/genetics
- Nuclear Pore Complex Proteins/metabolism
- RNA Interference
- RNA Processing, Post-Transcriptional
- RNA Stability
- RNA, Messenger/metabolism
- Time Factors
- Transfection
- Tumor Suppressor Protein p53/genetics
- Tumor Suppressor Protein p53/metabolism
- ATP-Binding Cassette Sub-Family B Member 4
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Affiliation(s)
- Stephan Singer
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
- Institute of Pathology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Ruiying Zhao
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Anthony M. Barsotti
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Anette Ouwehand
- Department of Bionanoscience, Kavli Institute of NanoScience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - Mina Fazollahi
- Department of Physics, Columbia University, New York, NY 10027, USA
- Center for Computational Biology and Bioinformatics, Columbia University, New York, NY 100
| | - Elias Coutavas
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10021, USA
| | - Kai Breuhahn
- Institute of Pathology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Olaf Neumann
- Institute of Pathology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Thomas Longerich
- Institute of Pathology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Tobias Pusterla
- Division of Signal Transduction and Growth Control, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Maureen A. Powers
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Keith M. Giles
- Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Perth 6000, Australia
| | - Peter J. Leedman
- Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Perth 6000, Australia
| | - Jochen Hess
- Junior Research Group Molecular Mechanisms of Head and Neck Tumors, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Department of Otolaryngology, Head and Neck Surgery, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - David Grunwald
- Department of Bionanoscience, Kavli Institute of NanoScience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - Harmen J. Bussemaker
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
- Center for Computational Biology and Bioinformatics, Columbia University, New York, NY 100
| | - Robert H. Singer
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Peter Schirmacher
- Institute of Pathology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Carol Prives
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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Yang Q, Lu Z, Singh D, Raj JU. BIX-01294 treatment blocks cell proliferation, migration and contractility in ovine foetal pulmonary arterial smooth muscle cells. Cell Prolif 2012; 45:335-44. [PMID: 22691107 DOI: 10.1111/j.1365-2184.2012.00828.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 03/27/2012] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE Recent studies have indicated a role of epigenetic phenomena in pathogenesis of pulmonary hypertension, but in foetal pulmonary artery smooth muscle cell (PASMC) proliferation this is still largely unknown. G9a is a key enzyme for histone H3 dimethylation at position lysine-9. In this study, we have investigated the function of G9a in ovine foetal PASMC proliferation, migration and contractility. MATERIAL AND METHODS Cell proliferation was measured by cell counting and BrdU incorporation assay and cell cycle analysis was performed by flow cytometry. Expression of cell cycle-related genes was determined by real-time PCR and the wound-healing scratch assay was used to measure cell migration. A gel contraction assay was used to determine contractility of foetal PASMCs. Global DNA methylation was measured by liquid chromatography-mass spectroscopy. RESULTS Inhibition of G9a by its inhibitor BIX-01294 reduced proliferation of foetal PASMCs and induced cell cycle arrest in G(1) phase. This was accompanied by increased p21 expression, but not p53 and other cell cycle-related genes. Treatment of foetal PASMCs with BIX-01294 inhibited platelet-derived growth factor-induced cell proliferation and migration. Contractility of foetal PASMCs was also markedly inhibited by BIX-01294. Expression of calponin and ROCK-II proteins was reduced by BIX-01294 in a dose-dependent manner and BIX-01294 significantly increased global methylation level in the foetal PASMCs. CONCLUSION Our results demonstrate for the first time that histone lysine methylation is involved in cell proliferation, migration, contractility and global DNA methylation in foetal PASMCs. Further understanding of this mechanism may provide insight into proliferative vascular disease in the lungs.
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Affiliation(s)
- Q Yang
- Department of Pediatrics, University of Illinois at Chicago, Chicago, IL 60612, USA.
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40
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Palusa S, Ndaluka C, Bowen RA, Wilusz CJ, Wilusz J. The 3' untranslated region of the rabies virus glycoprotein mRNA specifically interacts with cellular PCBP2 protein and promotes transcript stability. PLoS One 2012; 7:e33561. [PMID: 22438951 PMCID: PMC3306424 DOI: 10.1371/journal.pone.0033561] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 02/14/2012] [Indexed: 12/25/2022] Open
Abstract
Viral polymerase entry and pausing at intergenic junctions is predicted to lead to a defined polarity in the levels of rhabdovirus gene expression. Interestingly, we observed that the rabies virus glycoprotein mRNA is differentially over-expressed based on this model relative to other transcripts during infection of 293T cells. During infection, the rabies virus glycoprotein mRNA also selectively interacts with the cellular poly(rC)-binding protein 2 (PCBP2), a factor known to influence mRNA stability. Reporter assays performed both in electroporated cells and in a cell-free RNA decay system indicate that the conserved portion of the 3' UTR of the rabies virus glycoprotein mRNA contains an RNA stability element. PCBP2 specifically interacts with reporter transcripts containing this 72 base 3' UTR sequence. Furthermore, the PCBP2 interaction is directly associated with the stability of reporter transcripts. Therefore, we conclude that PCBP2 specifically and selectively interacts with the rabies virus glycoprotein mRNA and that this interaction may contribute to the post-transcriptional regulation of glycoprotein expression.
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Affiliation(s)
- Saiprasad Palusa
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Christina Ndaluka
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Richard A. Bowen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Carol J. Wilusz
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Jeffrey Wilusz
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
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41
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Poly(C)-binding protein 1 (PCBP1) mediates housekeeping degradation of mitochondrial antiviral signaling (MAVS). Cell Res 2011; 22:717-27. [PMID: 22105485 DOI: 10.1038/cr.2011.184] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial antiviral signaling (MAVS) is a key adaptor in cellular antiviral innate immunity. We previously identified poly(C)-binding protein 2 (PCBP2) as a feedback inhibitor of MAVS that facilitates its degradation after viral infection, but little is known about the regulatory potential of poly(C)-binding protein 1 (PCBP1), which highly resembles PCBP2. Here we report that PCBP1 mediates housekeeping degradation of MAVS using the same mechanism as PCBP2 employs. Overexpression of PCBP1 impairs MAVS-mediated antiviral responses, while knockdown of PCBP1 exerts the opposite effect. The suppression is due to PCBP1-induced MAVS degradation. We observe that PCBP1 and PCBP2 show synergy in MAVS inhibition, but their expression patterns are distinct: PCBP1 is stably and abundantly expressed, while PCBP2 shows low basal expression with rapid induction after infection. Individual knockdown and subcellular fractionation analyses reveal that unlike the postinfection inhibitor PCBP2, PCBP1 continuously eliminates cellular MAVS. Our findings unravel a critical role of PCBP1 in regulating MAVS for both fine-tuning the antiviral immunity and preventing inflammation.
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42
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Favreau AJ, Sathyanarayana P. miR-590-5p, miR-219-5p, miR-15b and miR-628-5p are commonly regulated by IL-3, GM-CSF and G-CSF in acute myeloid leukemia. Leuk Res 2011; 36:334-41. [PMID: 22015065 DOI: 10.1016/j.leukres.2011.09.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 09/21/2011] [Accepted: 09/22/2011] [Indexed: 12/19/2022]
Abstract
Aberrations in IL-3, GM-CSF and G-CSF induced signaling are frequently reported in acute myeloid leukemia (AML). Herein, we utilized a unique human myeloid leukemic cell line, AML-193, which responds to all three cytokines to analyze the regulation at microRNA level. Using real-time PCR-based miRNA expression profiling, we investigated miRNA signatures regulated by IL-3, GM-CSF and G-CSF for n=704 miRNAs. We discovered that in addition to regulating specific miRNAs, these cytokines also regulate common set of miRNAs, which includes miR-590-5p, miR-219-5p, miR-15b and miR-628-5p. Taken together, we have identified novel candidate miRNAs that may be instructive during leukemic and normal hematopoiesis.
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Affiliation(s)
- Amanda J Favreau
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME 04074, USA
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43
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Xin Z, Han W, Zhao Z, Xia Q, Yin B, Yuan J, Peng X. PCBP2 enhances the antiviral activity of IFN-α against HCV by stabilizing the mRNA of STAT1 and STAT2. PLoS One 2011; 6:e25419. [PMID: 22022391 PMCID: PMC3191149 DOI: 10.1371/journal.pone.0025419] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 09/03/2011] [Indexed: 11/28/2022] Open
Abstract
Interferon-α (IFN-α) is a natural choice for the treatment of hepatitis C, but half of the chronically infected individuals do not achieve sustained clearance of hepatitis C virus (HCV) during treatment with IFN-α alone. The virus can impair IFN-α signaling and cellular factors that have an effect on the viral life cycles. We found that the protein PCBP2 is down-regulated in HCV-replicon containing cells (R1b). However, the effects and mechanisms of PCBP2 on HCV are unclear. To determine the effect of PCBP2 on HCV, overexpression and knockdown of PCBP2 were performed in R1b cells. Interestingly, we found that PCBP2 can facilitate the antiviral activity of IFN-α against HCV, although the RNA level of HCV was unaffected by either the overexpression or absence of PCBP2 in R1b cells. RIP-qRT-PCR and RNA half-life further revealed that PCBP2 stabilizes the mRNA of STAT1 and STAT2 through binding the 3′Untranslated Region (UTR) of these two molecules, which are pivotal for the IFN-α anti-HCV effect. RNA pull-down assay confirmed that there were binding sites located in the C-rich tracts in the 3′UTR of their mRNAs. Stabilization of mRNA by PCBP2 leads to the increased protein expression of STAT1 and STAT2 and a consistent increase of phosphorylated STAT1 and STAT2. These effects, in turn, enhance the antiviral effect of IFN-α. These findings indicate that PCBP2 may play an important role in the IFN-α response against HCV and may benefit the HCV clinical therapy.
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Affiliation(s)
- Zhongshuai Xin
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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44
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Cellular poly(c) binding proteins 1 and 2 interact with porcine reproductive and respiratory syndrome virus nonstructural protein 1β and support viral replication. J Virol 2011; 85:12939-49. [PMID: 21976648 DOI: 10.1128/jvi.05177-11] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) infection of swine results in substantial economic losses to the swine industry worldwide. Identification of cellular factors involved in PRRSV life cycle not only will enable a better understanding of virus biology but also has the potential for the development of antiviral therapeutics. The PRRSV nonstructural protein 1 (nsp1) has been shown to be involved in at least two important functions in the infected hosts: (i) mediation of viral subgenomic (sg) mRNA transcription and (ii) suppression of the host's innate immune response mechanisms. To further our understanding of the role of the viral nsp1 in these processes, using nsp1β, a proteolytically processed functional product of nsp1 as bait, we have identified the cellular poly(C)-binding proteins 1 and 2 (PCBP1 and PCBP2) as two of its interaction partners. The interactions of PCBP1 and PCBP2 with nsp1β were confirmed both by coimmunoprecipitation in infected cells and/or in plasmid-transfected cells and also by in vitro binding assays. During PRRSV infection of MARC-145 cells, the cytoplasmic PCBP1 and PCBP2 partially colocalize to the viral replication-transcription complexes. Furthermore, recombinant purified PCBP1 and PCBP2 were found to bind the viral 5' untranslated region (5'UTR). Small interfering RNA (siRNA)-mediated silencing of PCBP1 and PCBP2 in cells resulted in significantly reduced PRRSV genome replication and transcription without adverse effect on initial polyprotein synthesis. Overall, the results presented here point toward an important role for PCBP1 and PCBP2 in regulating PRRSV RNA synthesis.
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45
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Zheng D, Chen CYA, Shyu AB. Unraveling regulation and new components of human P-bodies through a protein interaction framework and experimental validation. RNA (NEW YORK, N.Y.) 2011; 17:1619-34. [PMID: 21750099 PMCID: PMC3162328 DOI: 10.1261/rna.2789611] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The cellular factors involved in mRNA degradation and translation repression can aggregate into cytoplasmic domains known as GW bodies or mRNA processing bodies (P-bodies). However, current understanding of P-bodies, especially the regulatory aspect, remains relatively fragmentary. To provide a framework for studying the mechanisms and regulation of P-body formation, maintenance, and disassembly, we compiled a list of P-body proteins found in various species and further grouped both reported and predicted human P-body proteins according to their functions. By analyzing protein-protein interactions of human P-body components, we found that many P-body proteins form complex interaction networks with each other and with other cellular proteins that are not recognized as P-body components. The observation suggests that these other cellular proteins may play important roles in regulating P-body dynamics and functions. We further used siRNA-mediated gene knockdown and immunofluorescence microscopy to demonstrate the validity of our in silico analyses. Our combined approach identifies new P-body components and suggests that protein ubiquitination and protein phosphorylation involving 14-3-3 proteins may play critical roles for post-translational modifications of P-body components in regulating P-body dynamics. Our analyses provide not only a global view of human P-body components and their physical interactions but also a wealth of hypotheses to help guide future research on the regulation and function of human P-bodies.
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Affiliation(s)
- Dinghai Zheng
- Department of Biochemistry and Molecular Biology, The University of Texas Medical School, Houston, Texas 77021, USA
| | - Chyi-Ying A. Chen
- Department of Biochemistry and Molecular Biology, The University of Texas Medical School, Houston, Texas 77021, USA
| | - Ann-Bin Shyu
- Department of Biochemistry and Molecular Biology, The University of Texas Medical School, Houston, Texas 77021, USA
- Corresponding author.E-mail .
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46
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Dickson AM, Wilusz J. Strategies for viral RNA stability: live long and prosper. Trends Genet 2011; 27:286-93. [PMID: 21640425 PMCID: PMC3123725 DOI: 10.1016/j.tig.2011.04.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 04/21/2011] [Accepted: 04/26/2011] [Indexed: 12/23/2022]
Abstract
Eukaryotic cells have a powerful RNA decay machinery that plays an important and diverse role in regulating both the quantity and the quality of gene expression. Viral RNAs need to successfully navigate around this cellular machinery to initiate and maintain a highly productive infection. Recent work has shown that viruses have developed a variety of strategies to accomplish this, including inherent RNA shields, hijacking host RNA stability factors, incapacitating the host decay machinery and changing the entire landscape of RNA stability in cells using virally encoded nucleases. In addition to maintaining the stability of viral transcripts, these strategies can also contribute to the regulation and complexity of viral gene expression as well as to viral RNA evolution.
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47
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Antagonistic effects of cellular poly(C) binding proteins on vesicular stomatitis virus gene expression. J Virol 2011; 85:9459-71. [PMID: 21752917 DOI: 10.1128/jvi.05179-11] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Immunoprecipitation and subsequent mass spectrometry analysis of the cellular proteins from cells expressing the vesicular stomatitis virus (VSV) P protein identified the poly(C) binding protein 2 (PCBP2) as one of the P protein-interacting proteins. To investigate the role of PCBP2 in the viral life cycle, we examined the effects of depletion or overexpression of this protein on VSV growth. Small interfering RNA-mediated silencing of PCBP2 promoted VSV replication. Conversely, overexpression of PCBP2 in transfected cells suppressed VSV growth. Further studies revealed that PCBP2 negatively regulates overall viral mRNA accumulation and subsequent genome replication. Coimmunoprecipitation and immunofluorescence microscopic studies showed that PCBP2 interacts and colocalizes with VSV P protein in virus-infected cells. The P-PCBP2 interaction did not result in reduced levels of protein complex formation with the viral N and L proteins, nor did it induce degradation of the P protein. In addition, PCBP1, another member of the poly(C) binding protein family with homology to PCBP2, was also found to interact with the P protein and inhibit the viral mRNA synthesis at the level of primary transcription without affecting secondary transcription or genome replication. The inhibitory effects of PCBP1 on VSV replication were less pronounced than those of PCBP2. Overall, the results presented here suggest that cellular PCBP2 and PCBP1 antagonize VSV growth by affecting viral gene expression and highlight the importance of these two cellular proteins in restricting virus infections.
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48
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Perrotti D, Harb JG. BCR-ABL1 kinase-dependent alteration of mRNA metabolism: potential alternatives for therapeutic intervention. Leuk Lymphoma 2011; 52 Suppl 1:30-44. [PMID: 21299458 DOI: 10.3109/10428194.2010.546914] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The use of first- and second-generation tyrosine kinase inhibitors (TKIs) significantly improves prognosis for patients with early chronic phase chronic myeloid leukemia (CML) and efficiently counteracts leukemia in most patients with CML bearing a disease characterized by the expression of BCR-ABL1 mutants. However, the so-called 'tinib' TKIs (e.g. imatinib, nilotinib, dasatinib, and bosutinib) are both ineffective in patients who undergo blastic transformation and unable to eradicate CML at the stem cell level. This raises a few important questions. Is BCR-ABL1 expression and/or activity essential for blastic transformation? Is blastic transformation the result of genetic or epigenetic events that occur at the stem cell level which only become apparent in the granulocyte-macrophage progenitor (GMP) cell pool, or does it arise directly at the GMP level? As altered mRNA metabolism contributes to the phenotype of blast crisis CML progenitors (decreased translation of tumor suppressor genes and transcription factors essential for terminal differentiation and increased translation of anti-apoptotic genes), one attractive concept is to restore levels of these essential molecules to their normal levels. In this review, we discuss the mechanisms by which mRNA processing, translation, and degradation are deregulated in BCR-ABL1 myeloid blast crisis CML progenitors, and present encouraging results from studies with pharmacologic inhibitors which support their inclusion in the clinic.
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Affiliation(s)
- Danilo Perrotti
- Human Cancer Genetics Program, Depatment of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center and Center for RNA Biology, The Ohio State University, Columbus, OH 43210-2207, USA.
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49
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Hirsch CL, Ellis DJP, Bonham K. Histone deacetylase inhibitors mediate post-transcriptional regulation of p21WAF1 through novel cis-acting elements in the 3' untranslated region. Biochem Biophys Res Commun 2010; 402:687-92. [PMID: 20977880 DOI: 10.1016/j.bbrc.2010.10.085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 10/19/2010] [Indexed: 12/11/2022]
Abstract
Histone deacetylase inhibitors (HDACIs) are promising anti-tumor agents that selectively induce cell cycle arrest, differentiation and/or apoptosis of tumor cells. Fundamentally, HDACIs are proposed to function by activating the transcription of genes, including the potent cyclin dependent kinase inhibitor p21(WAF1). However, HDACIs primarily increase p21(WAF1) expression at the post-transcriptional level in HepG2 cells, implying that these anti-tumor agents regulate genes at multiple levels. Here, two novel cis-acting elements in the 3' untranslated region (UTR) of p21(WAF1) are identified that control the ability of HDACIs to induce p21(WAF1) mRNA stabilization. Collectively, these studies highlight the complexity of HDACIs in gene regulation.
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Affiliation(s)
- Calley L Hirsch
- Department of Biochemistry, University of Saskatchewan, Saskatoon, SK, Canada.
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50
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Scoumanne A, Cho SJ, Zhang J, Chen X. The cyclin-dependent kinase inhibitor p21 is regulated by RNA-binding protein PCBP4 via mRNA stability. Nucleic Acids Res 2010; 39:213-24. [PMID: 20817677 PMCID: PMC3017617 DOI: 10.1093/nar/gkq778] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
RNA-binding proteins (RBPs) play a major role in many post-transcriptional processes, including mRNA stability, alternative splicing and translation. PCBP4, also called MCG10, is an RBP belonging to the poly(C)-binding protein family and a target of p53 tumor suppressor. Ectopic expression of PCBP4 induces cell-cycle arrest in G2 and apoptosis. To identify RNA targets regulated by PCBP4 and further decipher its function, we generated multiple cell lines in which PCBP4 is either inducibly over-expressed or knocked down. We found that PCBP4 expression decreases cyclin-dependent kinase inhibitor p21 induction in response to DNA damage. We also provided evidence that PCBP4 regulates p21 expression independently of p53. In addition, we showed that a deficiency in PCBP4 enhances p21 induction upon DNA damage. To validate PCBP4 regulation of p21, we made PCBP4-deficient mice and showed that p21 expression is markedly increased in PCBP4-deficient primary mouse embryo fibroblasts compared to that in wild-type counterparts. Finally, we uncovered that PCBP4 binds to the 3′-UTR of p21 transcript in vitro and in vivo to regulate p21 mRNA stability. Taken together, we revealed that PCBP4 regulates both basal and stress-induced p21 expression through binding p21 3′-UTR and modulating p21 mRNA stability.
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Affiliation(s)
- Ariane Scoumanne
- The Center for Comparative Oncology, University of California at Davis, Davis, CA 95616, USA
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