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Higashiyama M, Haniuda K, Nihei Y, Kazuno S, Kikkawa M, Miura Y, Suzuki Y, Kitamura D. Oral bacteria induce IgA autoantibodies against a mesangial protein in IgA nephropathy model mice. Life Sci Alliance 2024; 7:e202402588. [PMID: 38331476 PMCID: PMC10853438 DOI: 10.26508/lsa.202402588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 01/25/2024] [Accepted: 01/25/2024] [Indexed: 02/10/2024] Open
Abstract
IgA nephropathy (IgAN) is caused by deposition of IgA in the glomerular mesangium. The mechanism of selective deposition and production of IgA is unclear; however, we recently identified the involvement of IgA autoantibodies. Here, we show that CBX3 is another self-antigen for IgA in gddY mice, a spontaneous IgAN model, and in IgAN patients. A recombinant antibody derived from gddY mice bound to CBX3 expressed on the mesangial cell surface in vitro and to glomeruli in vivo. An elemental diet and antibiotic treatment decreased the levels of autoantibodies and IgAN symptoms in gddY mice. Serum IgA and the recombinant antibody from gddY mice also bound to oral bacteria of the mice and binding was competed with CBX3. One species of oral bacteria was markedly decreased in elemental diet-fed gddY mice and induced anti-CBX3 antibody in normal mice upon immunization. These data suggest that particular oral bacteria generate immune responses to produce IgA that cross-reacts with mesangial cells to initiate IgAN.
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Affiliation(s)
- Mizuki Higashiyama
- https://ror.org/05sj3n476 Division of Cancer Cell Biology, Research Institute for Biomedical Sciences (RIBS), Tokyo University of Science, Noda, Japan
| | - Kei Haniuda
- https://ror.org/05sj3n476 Division of Cancer Cell Biology, Research Institute for Biomedical Sciences (RIBS), Tokyo University of Science, Noda, Japan
| | - Yoshihito Nihei
- https://ror.org/05sj3n476 Division of Cancer Cell Biology, Research Institute for Biomedical Sciences (RIBS), Tokyo University of Science, Noda, Japan
- Department of Nephrology, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Saiko Kazuno
- Laboratory of Proteomics and Biomolecular Science, Biomedical Research Core Facilities, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Mika Kikkawa
- Laboratory of Proteomics and Biomolecular Science, Biomedical Research Core Facilities, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yoshiki Miura
- Laboratory of Proteomics and Biomolecular Science, Biomedical Research Core Facilities, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yusuke Suzuki
- Department of Nephrology, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Daisuke Kitamura
- https://ror.org/05sj3n476 Division of Cancer Cell Biology, Research Institute for Biomedical Sciences (RIBS), Tokyo University of Science, Noda, Japan
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Pampanella L, Petrocelli G, Abruzzo PM, Zucchini C, Canaider S, Ventura C, Facchin F. Cytochalasins as Modulators of Stem Cell Differentiation. Cells 2024; 13:400. [PMID: 38474364 DOI: 10.3390/cells13050400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 02/16/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024] Open
Abstract
Regenerative medicine aims to identify new research strategies for the repair and restoration of tissues damaged by pathological or accidental events. Mesenchymal stem cells (MSCs) play a key role in regenerative medicine approaches due to their specific properties, such as the high rate of proliferation, the ability to differentiate into several cell lineages, the immunomodulatory potential, and their easy isolation with minimal ethical issues. One of the main goals of regenerative medicine is to modulate, both in vitro and in vivo, the differentiation potential of MSCs to improve their use in the repair of damaged tissues. Over the years, much evidence has been collected about the ability of cytochalasins, a large family of 60 metabolites isolated mainly from fungi, to modulate multiple properties of stem cells (SCs), such as proliferation, migration, and differentiation, by altering the organization of the cyto- and the nucleo-skeleton. In this review, we discussed the ability of two different cytochalasins, cytochalasins D and B, to influence specific SC differentiation programs modulated by several agents (chemical or physical) or intra- and extra-cellular factors, with particular attention to human MSCs (hMSCs).
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Affiliation(s)
- Luca Pampanella
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Via Massarenti 9, 40138 Bologna, Italy
| | - Giovannamaria Petrocelli
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Via Massarenti 9, 40138 Bologna, Italy
| | - Provvidenza Maria Abruzzo
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Via Massarenti 9, 40138 Bologna, Italy
| | - Cinzia Zucchini
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Via Massarenti 9, 40138 Bologna, Italy
| | - Silvia Canaider
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Via Massarenti 9, 40138 Bologna, Italy
| | - Carlo Ventura
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Via Massarenti 9, 40138 Bologna, Italy
- National Laboratory of Molecular Biology and Stem Cell Bioengineering of the National Institute of Biostructures and Biosystems (NIBB) c/o Eldor Lab, Via Corticella 183, 40129 Bologna, Italy
| | - Federica Facchin
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Via Massarenti 9, 40138 Bologna, Italy
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Characterization of a Novel Heterochromatin Protein 1 Homolog “HP1c” in the Silkworm, Bombyx mori. INSECTS 2022; 13:insects13070631. [PMID: 35886807 PMCID: PMC9316600 DOI: 10.3390/insects13070631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/09/2022] [Accepted: 07/11/2022] [Indexed: 12/04/2022]
Abstract
Simple Summary Heterochromatin protein 1 (HP1) plays a major role in the formation and maintenance of heterochromatin and in the regulation of gene expression. Five HP1 genes have been found in Drosophila melanogaster and three HP1 genes in Homo sapiens, while in Bombyx mori, two HP1 genes (BmHP1a and BmHP1b) have been reported. In the present study, we analyzed the function of the novel Bombyx mori HP1 gene (BmHP1c), the third HP1 gene in silkworm. BmHP1c has different characteristics from BmHP1a and BmHP1b in terms of transcriptional repression activity, dimer formation, subcellular localization, and effects of RNAi on cell cycle progression. These findings indicate that BmHP1c plays a different role than BmHP1a and BmHP1b. Abstract Heterochromatin protein 1 plays an important role in chromatin structure and gene expression regulation. Three HP1 genes have been found in Homo sapiens, and five HP1 genes have been reported in Drosophila melanogaster. On the other hand, in Bombyx mori, only two HP1 genes, BmHP1a and BmHP1b, were reported. In this research, we have reported the molecular and functional characterization of a novel Bombyx mori HP1 gene (BmHP1c), which had stronger transcriptional repression activity than BmHP1a. BmHP1a and BmHP1b is reported to form homo- and heterodimers, but in co-immunoprecipitation experiments, no homo- or hetero-dimer formation of BmHP1c with the other silkworm HP1s is detected. The intracellular localization of BmHP1c is not only in the nucleus but also in the cytoplasm like mammalian HP1γ. In contrast to human HP1a and b, all three BmHP1s were localized preferentially in the regions poorly stained with DAPI. Interestingly, the double knockdown of BmHP1a and b, but not BmHP1c with a or b, arrested the cell cycle at the G2/M phase. These results suggest that BmHP1c is not essential for cell progression and plays a different role than BmHP1a and BmHP1b.
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Kleene R, Loers G, Castillo G, Schachner M. Cell adhesion molecule L1 interacts with the chromo shadow domain of heterochromatin protein 1 isoforms α, β, and ɣ via its intracellular domain. FASEB J 2021; 36:e22074. [PMID: 34859928 DOI: 10.1096/fj.202100816r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 11/01/2021] [Accepted: 11/15/2021] [Indexed: 11/11/2022]
Abstract
Cell adhesion molecule L1 regulates multiple cell functions and L1 deficiency is linked to several neural diseases. Proteolytic processing generates functionally decisive L1 fragments, which are imported into the nucleus. By computational analysis, we found at L1's C-terminal end the chromo shadow domain-binding motif PxVxL, which directs the binding of nuclear proteins to the heterochromatin protein 1 (HP1) isoforms α, β, and ɣ. By enzyme-linked immunosorbent assay, we show that the intracellular L1 domain binds to all HP1 isoforms. These interactions involve the HP1 chromo shadow domain and are mediated via the sequence 1158 KDET1161 in the intracellular domain of murine L1, but not by L1's C-terminal PxVxL motif. Immunoprecipitation using nuclear extracts from the brain and from cultured cerebellar and cortical neurons indicates that HP1 isoforms interact with a yet unknown nuclear L1 fragment of approximately 55 kDa (L1-55), which carries ubiquitin residues. Proximity ligation indicates a close association between L1-55 and the HP1 isoforms in neuronal nuclei. This association is reduced after the treatment of neurons with inhibitors of metalloproteases, β-site of amyloid precursor protein cleaving enzyme (BACE1), or ɣ-secretase, suggesting that cleavage of full-length L1 by these proteases generates L1-55. Reduction of HP1α, -β, or -ɣ expression by siRNA decreases L1-dependent neurite outgrowth from cultured cortical neurons and decreases the L1-dependent migration of L1-transfected HEK293 cells in a scratch assay. These findings indicate that the interaction of the novel fragment L1-55 with HP1 isoforms in nuclei affects L1-dependent functions, such as neurite outgrowth and neuronal migration.
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Affiliation(s)
- Ralf Kleene
- Research Group Biosynthesis of Neural Structures, Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Gabriele Loers
- Research Group Biosynthesis of Neural Structures, Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Gaston Castillo
- Research Group Biosynthesis of Neural Structures, Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Melitta Schachner
- Department of Cell Biology and Neuroscience, Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway, New Jersey, USA
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Cai H, Yu Y, Ni X, Li C, Hu Y, Wang J, Chen F, Xi S, Chen Z. LncRNA LINC00998 inhibits the malignant glioma phenotype via the CBX3-mediated c-Met/Akt/mTOR axis. Cell Death Dis 2020; 11:1032. [PMID: 33268783 PMCID: PMC7710718 DOI: 10.1038/s41419-020-03247-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 11/12/2020] [Accepted: 11/16/2020] [Indexed: 12/20/2022]
Abstract
Long noncoding RNAs (lncRNAs), once considered to be nonfunctional relics of evolution, are emerging as essential genes in tumor progression. However, the function and underlying mechanisms of lncRNAs in glioma remain unclear. This study aimed to investigate the role of LINC00998 in glioma progression. Through screening using TCGA database, we found that LINC00998 was downregulated in glioblastoma tissues and that low expression of LINC00998 was associated with poor prognosis. Overexpression of LINC00998 inhibited glioma cell proliferation in vitro and in vivo and blocked the G1/S cell cycle transition, which exerted a tumor-suppressive effect on glioma progression. Mechanistically, RNA pull-down and mass spectrometry results showed an interaction between LINC00998 and CBX3. IP assays demonstrated that LINC00998 could stabilize CBX3 and prevent its ubiquitination degradation. GSEA indicated that LINC00998 could regulate the c-Met/Akt/mTOR signaling pathway, which was further confirmed by a rescue assay using siRNA-mediated knockdown of CBX3 and the Akt inhibitor MK2206. In addition, dual-luciferase assays showed that miR-34c-5p could directly bind to LINC00998 and downregulate its expression. Our results identified LINC00998 as a novel tumor suppressor in glioma, and LINC00998 could be a novel prognostic biomarker, providing a strategy for precision therapy in glioma patients.
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Affiliation(s)
- Haiping Cai
- Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, 510060, PR China
| | - Yanjiao Yu
- Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, 510060, PR China
| | - Xiangrong Ni
- Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, 510060, PR China
| | - Cong Li
- Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, 510060, PR China
| | - Yuanjun Hu
- Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, 510060, PR China
| | - Jing Wang
- Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, 510060, PR China
| | - Furong Chen
- Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, 510060, PR China
| | - Shaoyan Xi
- Department of Pathology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, 510060, PR China.
| | - Zhongping Chen
- Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, 510060, PR China.
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Yi SA, Lee DH, Kim GW, Ryu HW, Park JW, Lee J, Han J, Park JH, Oh H, Lee J, Choi J, Kim HS, Kang HG, Kim DH, Chun KH, You JS, Han JW, Kwon SH. HPV-mediated nuclear export of HP1γ drives cervical tumorigenesis by downregulation of p53. Cell Death Differ 2020; 27:2537-2551. [PMID: 32203172 PMCID: PMC7429875 DOI: 10.1038/s41418-020-0520-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 02/19/2020] [Accepted: 02/20/2020] [Indexed: 12/20/2022] Open
Abstract
E6 oncoprotein derived from high-risk human papillomavirus (HPV) drives the development of cervical cancer through p53 degradation. Because cervical cancer therapies to inactivate HPV or E6 protein are not available, alternative strategies are required. Here, we show that HPV-mediated nuclear export of human heterochromatin protein 1γ (HP1γ) reduces the stability of p53 through UBE2L3-mediated p53 polyubiquitination during cervical cancer progression. In general, HP1 plays a key role in heterochromatin formation and transcription in the nucleus. However, our immunostaining data showed that the majority of HP1γ is localized in the cytoplasm in HPV-mediated cervical cancer. We found that HPV E6 protein drives unusual nuclear export of HP1γ through the interaction between the NES sequence of HP1γ and exportin-1. The mutation of the NES sequence in HP1γ led to nuclear retention of HP1γ and reduced cervical cancer cell growth and tumor generation. We further discovered that HP1γ directly suppresses the expression of UBE2L3 which drives E6-mediated proteasomal degradation of p53 in cervical cancer. Downregulation of UBE2L3 by overexpression of HP1γ suppressed UBE2L3-dependent p53 degradation-promoting apoptosis of cervical cancer cells. Our findings propose a useful strategy to overcome p53 degradation in cervical cancer through the blockage of nuclear export of HP1γ.
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Affiliation(s)
- Sang Ah Yi
- Epigenome Dynamics Control Research Center, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Dong Hoon Lee
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, 21983, Republic of Korea
| | - Go Woon Kim
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, 21983, Republic of Korea
| | - Hyun-Wook Ryu
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, 21983, Republic of Korea
| | - Jong Woo Park
- Epigenome Dynamics Control Research Center, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Jaecheol Lee
- Epigenome Dynamics Control Research Center, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Jihoon Han
- Epigenome Dynamics Control Research Center, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Jee Hun Park
- Epigenome Dynamics Control Research Center, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Hwamok Oh
- Epigenome Dynamics Control Research Center, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Jieun Lee
- Epigenome Dynamics Control Research Center, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Junjeong Choi
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, 21983, Republic of Korea
| | - Hyun-Soo Kim
- Department of Pathology, Severance Hospital, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Hyeok Gu Kang
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Da-Hyun Kim
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Kyung-Hee Chun
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Jueng Soo You
- Department of Biochemistry, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea
| | - Jeung-Whan Han
- Epigenome Dynamics Control Research Center, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
| | - So Hee Kwon
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, 21983, Republic of Korea.
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Kumar A, Kono H. Heterochromatin protein 1 (HP1): interactions with itself and chromatin components. Biophys Rev 2020; 12:387-400. [PMID: 32144738 PMCID: PMC7242596 DOI: 10.1007/s12551-020-00663-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 02/23/2020] [Indexed: 12/12/2022] Open
Abstract
Isoforms of heterochromatin protein 1 (HP1) have been known to perform a multitude of functions ranging from gene silencing, gene activation to cell cycle regulation, and cell differentiation. This functional diversity arises from the dissimilarities coded in protein sequence which confers different biophysical and biochemical properties to individual structural elements of HP1 and thereby different behavior and interaction patterns. Hence, an understanding of various interactions of the structural elements of HP1 will be of utmost importance to better elucidate chromatin dynamics in its presence. In this review, we have gathered available information about interactions of HP1 both within and with itself as well as with chromatin elements. Also, the possible implications of these interactions are discussed.
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Affiliation(s)
- Amarjeet Kumar
- Molecular Modelling and Simulation (MMS) Group, Institute for Quantum Life Science (iQLS), National Institutes for Quantum and Radiological Science and Technology (QST), Kizugawa, Kyoto, 619-0215, Japan
| | - Hidetoshi Kono
- Molecular Modelling and Simulation (MMS) Group, Institute for Quantum Life Science (iQLS), National Institutes for Quantum and Radiological Science and Technology (QST), Kizugawa, Kyoto, 619-0215, Japan.
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Galigniana NM, Charó NL, Uranga R, Cabanillas AM, Piwien-Pilipuk G. Oxidative stress induces transcription of telomeric repeat-containing RNA (TERRA) by engaging PKA signaling and cytoskeleton dynamics. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118643. [DOI: 10.1016/j.bbamcr.2020.118643] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 12/27/2019] [Accepted: 01/02/2020] [Indexed: 12/11/2022]
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Mathison A, Milech De Assuncao T, Dsouza NR, Williams M, Zimmermann MT, Urrutia R, Lomberk G. Discovery, expression, cellular localization, and molecular properties of a novel, alternative spliced HP1γ isoform, lacking the chromoshadow domain. PLoS One 2020; 15:e0217452. [PMID: 32027651 PMCID: PMC7004349 DOI: 10.1371/journal.pone.0217452] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 01/16/2020] [Indexed: 12/13/2022] Open
Abstract
By reading the H3K9Me3 mark through their N-terminal chromodomain (CD), HP1 proteins play a significant role in cancer-associated processes, including cell proliferation, differentiation, chromosomal stability, and DNA repair. Here, we used a combination of bioinformatics-based methodologies, as well as experimentally-derived datasets, that reveal the existence of a novel short HP1γ (CBX3) isoform, named here sHP1γ, generated by alternative splicing of the CBX3 locus. The sHP1γ mRNA encodes a protein composed of 101 residues and lacks the C-terminal chromoshadow domain (CSD) that is required for dimerization and heterodimerization in the previously described 183 a. a HP1γ protein. Fold recognition, order-to-disorder calculations, threading, homology-based molecular modeling, docking, and molecular dynamic simulations show that the sHP1γ is comprised of a CD flanked by intrinsically disordered regions (IDRs) with an IDR-CD-IDR domain organization and likely retains the ability to bind to the H3K9Me3. Both qPCR analyses and mRNA-seq data derived from large-scale studies confirmed that sHP1γ mRNA is expressed in the majority of human tissues at approximately constant ratios with the chromoshadow domain containing isoform. However, sHP1γ mRNA levels appear to be dysregulated in different cancer types. Thus, our data supports the notion that, due to the existence of functionally different isoforms, the regulation of HP1γ-mediated functions is more complex than previously anticipated.
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Affiliation(s)
- Angela Mathison
- Genomics and Precision Medicine Center (GSPMC), Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Division of Research, Department of Surgery, Medical College of Wisconsin, WI Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Thiago Milech De Assuncao
- Genomics and Precision Medicine Center (GSPMC), Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Division of Research, Department of Surgery, Medical College of Wisconsin, WI Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Nikita R. Dsouza
- Bioinformatics Research and Development Laboratory, and Precision Medicine Simulation Unit, Genomics and Precision Medicine Center (GSPMC), Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Monique Williams
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Michael T. Zimmermann
- Bioinformatics Research and Development Laboratory, and Precision Medicine Simulation Unit, Genomics and Precision Medicine Center (GSPMC), Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Clinical and Translational Sciences Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Raul Urrutia
- Genomics and Precision Medicine Center (GSPMC), Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Division of Research, Department of Surgery, Medical College of Wisconsin, WI Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Gwen Lomberk
- Genomics and Precision Medicine Center (GSPMC), Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Division of Research, Department of Surgery, Medical College of Wisconsin, WI Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
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