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Fukumura K, Sperotto L, Seuß S, Kang HS, Yoshimoto R, Sattler M, Mayeda A. SAP30BP interacts with RBM17/SPF45 to promote splicing in a subset of human short introns. Cell Rep 2023; 42:113534. [PMID: 38065098 DOI: 10.1016/j.celrep.2023.113534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 11/03/2023] [Accepted: 11/16/2023] [Indexed: 12/30/2023] Open
Abstract
Human pre-mRNA splicing requires the removal of introns with highly variable lengths, from tens to over a million nucleotides. Therefore, mechanisms of intron recognition and splicing are likely not universal. Recently, we reported that splicing in a subset of human short introns with truncated polypyrimidine tracts depends on RBM17 (SPF45), instead of the canonical splicing factor U2 auxiliary factor (U2AF) heterodimer. Here, we demonstrate that SAP30BP, a factor previously implicated in transcriptional control, is an essential splicing cofactor for RBM17. In vitro binding and nuclear magnetic resonance analyses demonstrate that a U2AF-homology motif (UHM) in RBM17 binds directly to a newly identified UHM-ligand motif in SAP30BP. We show that this RBM17-SAP30BP interaction is required to specifically recruit RBM17 to phosphorylated SF3B1 (SF3b155), a U2 small nuclear ribonucleoprotein (U2 snRNP) component in active spliceosomes. We propose a mechanism for splicing in a subset of short introns, in which SAP30BP guides RBM17 in the assembly of active spliceosomes.
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Affiliation(s)
- Kazuhiro Fukumura
- Division of Gene Expression Mechanism, Center for Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
| | - Luca Sperotto
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Bavarian NMR Center, TUM School of Natural Sciences, 85748 Garching, Germany
| | - Stefanie Seuß
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Bavarian NMR Center, TUM School of Natural Sciences, 85748 Garching, Germany
| | - Hyun-Seo Kang
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Bavarian NMR Center, TUM School of Natural Sciences, 85748 Garching, Germany
| | - Rei Yoshimoto
- Department of Applied Biological Sciences, Faculty of Agriculture, Setsunan University, Hirakata, Osaka 673-0101, Japan
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Bavarian NMR Center, TUM School of Natural Sciences, 85748 Garching, Germany
| | - Akila Mayeda
- Division of Gene Expression Mechanism, Center for Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
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Barbutti I, Machado-Neto JA, Arfelli VC, de Melo Campos P, Traina F, Saad STO, Archangelo LF. The U2AF homology motif kinase 1 (UHMK1) is upregulated upon hematopoietic cell differentiation. Biochim Biophys Acta Mol Basis Dis 2018; 1864:959-966. [PMID: 29307747 DOI: 10.1016/j.bbadis.2018.01.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 12/10/2017] [Accepted: 01/03/2018] [Indexed: 01/05/2023]
Abstract
UHMK1 (KIS) is a nuclear serine/threonine kinase that possesses a U2AF homology motif and phosphorylates and regulates the activity of the splicing factors SF1 and SF3b155. Mutations in these components of the spliceosome machinery have been recently implicated in leukemogenesis. The fact that UHMK1 regulates these factors suggests that UHMK1 might be involved in RNA processing and perhaps leukemogenesis. Here we analyzed UHMK1 expression in normal hematopoietic and leukemic cells as well as its function in leukemia cell line. In the normal hematopoietic compartment, markedly higher levels of transcripts were observed in differentiated lymphocytes (CD4+, CD8+ and CD19+) compared to the progenitor enriched subpopulation (CD34+) or leukemia cell lines. UHMK1 expression was upregulated in megakaryocytic-, monocytic- and granulocytic-induced differentiation of established leukemia cell lines and in erythrocytic-induced differentiation of CD34+ cells. No aberrant expression was observed in patient samples of myelodysplastic syndrome (MDS), acute myeloid (AML) or lymphoblastic (ALL) leukemia. Nonetheless, in MDS patients, increased levels of UHMK1 expression positively impacted event free and overall survival. Lentivirus mediated UHMK1 knockdown did not affect proliferation, cell cycle progression, apoptosis or migration of U937 leukemia cells, although UHMK1 silencing strikingly increased clonogenicity of these cells. Thus, our results suggest that UHMK1 plays a role in hematopoietic cell differentiation and suppression of autonomous clonal growth of leukemia cells.
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Affiliation(s)
- Isabella Barbutti
- Hematology and Transfusion Medicine Center, State University of Campinas (UNICAMP), Carlos Chagas 480, 13083-878 Campinas, SP, Brazil
| | - João Agostinho Machado-Neto
- Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Vanessa Cristina Arfelli
- Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Paula de Melo Campos
- Hematology and Transfusion Medicine Center, State University of Campinas (UNICAMP), Carlos Chagas 480, 13083-878 Campinas, SP, Brazil
| | - Fabiola Traina
- Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Sara Teresinha Olalla Saad
- Hematology and Transfusion Medicine Center, State University of Campinas (UNICAMP), Carlos Chagas 480, 13083-878 Campinas, SP, Brazil
| | - Leticia Fröhlich Archangelo
- Hematology and Transfusion Medicine Center, State University of Campinas (UNICAMP), Carlos Chagas 480, 13083-878 Campinas, SP, Brazil; Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
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