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Schabla NM, Perry GA, Palmer VL, Swanson PC. VprBP (DCAF1) Regulates RAG1 Expression Independently of Dicer by Mediating RAG1 Degradation. THE JOURNAL OF IMMUNOLOGY 2018; 201:930-939. [PMID: 29925675 DOI: 10.4049/jimmunol.1800054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 06/03/2018] [Indexed: 12/21/2022]
Abstract
The assembly of Ig genes in developing B lymphocytes by V(D)J recombination is initiated by the RAG1-RAG2 endonuclease complex. We previously identified an interaction between RAG1 and viral protein R binding protein (VprBP) (also known as DNA damage binding protein 1 cullin 4-associated factor 1 [DCAF1]), a substrate receptor for the cullin 4-really interesting new gene (RING) E3 ubiquitin ligase (CRL4). We report in this article that in mice, B cell-intrinsic loss of VprBP increases RAG1 protein levels and disrupts expression of the endoribonuclease Dicer, which is essential for microRNA maturation. Rag1/2 transcription is known to be derepressed by loss of microRNA-mediated suppression of phosphatase and tensin homolog, raising the possibility that the elevated level of RAG1 observed in VprBP-deficient B cells is caused indirectly by the loss of Dicer. However, we show that VprBP restrains RAG1 expression posttranscriptionally and independently of Dicer. Specifically, loss of VprBP stabilizes RAG1 protein, which we show is normally degraded via a mechanism requiring both 20S proteasome and cullin-RING E3 ubiquitin ligase activity. Furthermore, we show that RAG1 stabilization through small molecule inhibition of cullin-RING E3 ubiquitin ligase activation promotes V(D)J recombination in a murine pre-B cell line. Thus, in addition to identifying a role for VprBP in maintaining Dicer levels in B cells, our findings reveal the basis for RAG1 turnover and provide evidence that the CRL4VprBP(DCAF1) complex functions to maintain physiological levels of V(D)J recombination.
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Affiliation(s)
- N Max Schabla
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE 68178
| | - Greg A Perry
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE 68178
| | - Victoria L Palmer
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE 68178
| | - Patrick C Swanson
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE 68178
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Xiao M, Li J, Li W, Wang Y, Wu F, Xi Y, Zhang L, Ding C, Luo H, Li Y, Peng L, Zhao L, Peng S, Xiao Y, Dong S, Cao J, Yu W. MicroRNAs activate gene transcription epigenetically as an enhancer trigger. RNA Biol 2016; 14:1326-1334. [PMID: 26853707 PMCID: PMC5711461 DOI: 10.1080/15476286.2015.1112487] [Citation(s) in RCA: 218] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
MicroRNAs (miRNAs) are small non-coding RNAs that function as negative gene expression regulators. Emerging evidence shows that, except for function in the cytoplasm, miRNAs are also present in the nucleus. However, the functional significance of nuclear miRNAs remains largely undetermined. By screening miRNA database, we have identified a subset of miRNA that functions as enhancer regulators. Here, we found a set of miRNAs show gene-activation function. We focused on miR-24-1 and found that this miRNA unconventionally activates gene transcription by targeting enhancers. Consistently, the activation was completely abolished when the enhancer sequence was deleted by TALEN. Furthermore, we found that miR-24-1 activates enhancer RNA (eRNA) expression, alters histone modification, and increases the enrichment of p300 and RNA Pol II at the enhancer locus. Our results demonstrate a novel mechanism of miRNA as an enhancer trigger.
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Affiliation(s)
- Min Xiao
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China.,c Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University , Shanghai , China
| | - Jin Li
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China.,c Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University , Shanghai , China
| | - Wei Li
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China.,c Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University , Shanghai , China
| | - Yu Wang
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China
| | - Feizhen Wu
- d Laboratory of Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China
| | - Yanping Xi
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China
| | - Lan Zhang
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China
| | - Chao Ding
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,e The Experimental Training Center for Basic Medical Sciences, The Second Military Medical University , Shanghai , China
| | - Huaibing Luo
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China
| | - Yan Li
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China
| | - Lina Peng
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China
| | - Liping Zhao
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China
| | - Shaoliang Peng
- f School of Computer Science & State Key Laboratory of High Performance Computing, National University of Defense Technology , Changsha , China
| | - Yao Xiao
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China
| | - Shihua Dong
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China
| | - Jie Cao
- e The Experimental Training Center for Basic Medical Sciences, The Second Military Medical University , Shanghai , China
| | - Wenqiang Yu
- a Laboratory of RNA Epigenetics , Institutes of Biomedical Sciences & Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Ministry of Education , Department of Molecular Biology, Fudan University , Shanghai , China.,c Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University , Shanghai , China
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