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Loss of Arp1, a putative actin-related protein, triggers filamentous and invasive growth and impairs pathogenicity in Candida albicans. Comput Struct Biotechnol J 2020; 18:4002-4015. [PMID: 33363697 PMCID: PMC7744652 DOI: 10.1016/j.csbj.2020.11.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/19/2020] [Accepted: 11/21/2020] [Indexed: 12/27/2022] Open
Abstract
The polymorphous cellular shape of Candida albicans, in particular the transition from a yeast to a filamentous form, is crucial for either commensalism or life-threatening infections of the host. Various external or internal stimuli, including serum and nutrition starvation, have been shown to regulate filamentous growth primarily through two classical signaling pathways, the cAMP-PKA and the MAPK pathways. Genotoxic stress also induces filamentous growth, but through independent pathways, and little is known about negative regulation during this reversible morphological transition. In this study, we established that ARP1 in C. albicans, similar to its homolog in S. cerevisiae, has a role in nuclei separation and spindle orientation. Deletion of ARP1 generated filamentous and invasive growth as well as increased biofilm formation, accompanied by up-regulation of hyphae specific genes, such as HWP1, UME6 and ALS3. The filamentous and invasive growth of the ARP1 deletion strain was independent of transcription factors Efg1, Cph1 and Ume6, but was suppressed by deleting checkpoint BUB2 or overexpressing NRG1. Deletion of ARP1 impaired the colonization of Candida cells in mice and also attenuated virulence in a mouse model. All the data suggest that loss of ARP1 activates filamentous and invasive growth in vitro, and that it positively regulates virulence in vivo, which provides insight into actin-related morphology and pathogenicity in C. albicans.
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2
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Peng AYT, Kolhe JA, Behrens LD, Freeman BC. Genome organization: Tag it, move it, place it. Curr Opin Cell Biol 2020; 68:90-97. [PMID: 33166737 DOI: 10.1016/j.ceb.2020.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/28/2020] [Accepted: 10/08/2020] [Indexed: 12/14/2022]
Abstract
Chromosomes are selectively organized within the nuclei of interphase cells reflecting the current fate of each cell and are reorganized in response to various physiological cues to maintain homeostasis. Although substantial progress is being made to establish the various patterns of genome architecture, less is understood on how chromosome folding/positioning is achieved. Here, we discuss recent insights into the cellular mechanisms dictating chromatin movements including the use of epigenetic modifications and allosterically regulated transcription factors, as well as a nucleoskeleton system comprised of actin, myosin, and actin-binding proteins. Together, these nuclear factors help coordinate the positioning of both general and cell-specific genomic architectural features.
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Affiliation(s)
- Audrey Yi Tyan Peng
- University of Illinois, Urbana-Champaign, Department of Cell and Developmental Biology, Urbana, IL, 61801, USA
| | - Janhavi A Kolhe
- University of Illinois, Urbana-Champaign, Department of Cell and Developmental Biology, Urbana, IL, 61801, USA
| | - Lindsey D Behrens
- University of Illinois, Urbana-Champaign, Department of Cell and Developmental Biology, Urbana, IL, 61801, USA
| | - Brian C Freeman
- University of Illinois, Urbana-Champaign, Department of Cell and Developmental Biology, Urbana, IL, 61801, USA.
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3
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Venit T, Mahmood SR, Endara-Coll M, Percipalle P. Nuclear actin and myosin in chromatin regulation and maintenance of genome integrity. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 355:67-108. [DOI: 10.1016/bs.ircmb.2020.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
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4
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Wang D, Liu H, Ren C, Wang L. High Expression of ABRACL Is Associated with Tumorigenesis and Affects Clinical Outcome in Gastric Cancer. Genet Test Mol Biomarkers 2019; 23:91-97. [PMID: 30676103 DOI: 10.1089/gtmb.2018.0195] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The ABRA C-terminal like (ABRACL) protein belongs to a novel family of low-molecular weight proteins that increase actin dynamics and cell motility. It is involved in various diseases including cancer; however, its role in gastric cancer is unclear. In this study, the expression of ABRACL in gastric cancer and its relationships with patients' clinicopathological features and survival are examined. METHODS Sample expression profiles were downloaded from the Gene Expression Omnibus database and the Cancer Genome Atlas. ABRACL expression at the protein level in normal gastric and gastric cancer tissues was compared by using immunohistochemistry staining data provided by the Human Protein Atlas. Correlations between ABRACL expression and clinicopathological features are analyzed by chi-square tests. Patient survival was evaluated by Kaplan-Meier analysis. RESULTS ABRACL expression is upregulated in gastric cancer tissues than in normal tissues. High ABRACL levels indicated a poor prognosis. ABRACL expression (low ABRACL, n = 96; high ABRACL, n = 96) in gastric cancer tissues (primary data from GSE15459) is significantly correlated with poor overall survival (χ2 = 4.078, p = 0.043; log-rank test). ABRACL protein levels (low ABRACL, n = 172, high ABRACL, n = 171) in gastric cancer tissues (primary data from www.kmplot.com ) are significantly correlated with poor overall survival (χ2 = 4.305, p = 0.038, log-rank test). CONCLUSIONS Our results indicate that ABRACL is highly expressed in gastric cancer and is a potential prognostic marker and therapeutic target for this disease.
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Affiliation(s)
- Dazhi Wang
- 1 Pharmacy Department, Qingdao Municipal Hospital, Qingdao, China.,2 Cheeloo College of Medicine, Shandong University, Jinan, China
| | - HuaQiang Liu
- 1 Pharmacy Department, Qingdao Municipal Hospital, Qingdao, China
| | - Chunling Ren
- 3 Pharmacy Department, Qingdao Women and Children's Hospital, School of Medicine, Qingdao University, Qingdao, China
| | - Lanying Wang
- 1 Pharmacy Department, Qingdao Municipal Hospital, Qingdao, China
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5
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Klages-Mundt NL, Kumar A, Zhang Y, Kapoor P, Shen X. The Nature of Actin-Family Proteins in Chromatin-Modifying Complexes. Front Genet 2018; 9:398. [PMID: 30319687 PMCID: PMC6167448 DOI: 10.3389/fgene.2018.00398] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/31/2018] [Indexed: 01/25/2023] Open
Abstract
Actin is not only one of the most abundant proteins in eukaryotic cells, but also one of the most versatile. In addition to its familiar involvement in enabling contraction and establishing cellular motility and scaffolding in the cytosol, actin has well-documented roles in a variety of processes within the confines of the nucleus, such as transcriptional regulation and DNA repair. Interestingly, monomeric actin as well as actin-related proteins (Arps) are found as stoichiometric subunits of a variety of chromatin remodeling complexes and histone acetyltransferases, raising the question of precisely what roles they serve in these contexts. Actin and Arps are present in unique combinations in chromatin modifiers, helping to establish structural integrity of the complex and enabling a wide range of functions, such as recruiting the complex to nucleosomes to facilitate chromatin remodeling and promoting ATPase activity of the catalytic subunit. Actin and Arps are also thought to help modulate chromatin dynamics and maintain higher-order chromatin structure. Moreover, the presence of actin and Arps in several chromatin modifiers is necessary for promoting genomic integrity and an effective DNA damage response. In this review, we discuss the involvement of actin and Arps in these nuclear complexes that control chromatin remodeling and histone modifications, while also considering avenues for future study to further shed light on their functional importance.
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Affiliation(s)
- Naeh L Klages-Mundt
- Science Park Research Division, Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, United States.,Program in Genetics & Epigenetics, The University of Texas MD Anderson Cancer Center, UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Ashok Kumar
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX, United States
| | - Yuexuan Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Prabodh Kapoor
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX, United States
| | - Xuetong Shen
- Science Park Research Division, Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, United States.,Program in Genetics & Epigenetics, The University of Texas MD Anderson Cancer Center, UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
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6
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Nakamura R, Koshiba-Takeuchi K, Tsuchiya M, Kojima M, Miyazawa A, Ito K, Ogawa H, Takeuchi JK. Expression analysis of Baf60c during heart regeneration in axolotls and neonatal mice. Dev Growth Differ 2016; 58:367-82. [PMID: 27125315 DOI: 10.1111/dgd.12281] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/01/2016] [Accepted: 03/01/2016] [Indexed: 01/14/2023]
Abstract
Some organisms, such as zebrafish, urodele amphibians, and newborn mice, have a capacity for heart regeneration following injury. However, adult mammals fail to regenerate their hearts. To know why newborn mice can regenerate their hearts, we focused on epigenetic factors, which are involved in cell differentiation in many tissues. Baf60c (BRG1/BRM-associated factor 60c), a component of ATP-dependent chromatin-remodeling complexes, has an essential role for cardiomyocyte differentiation at the early heart development. To address the function of Baf60c in postnatal heart homeostasis and regeneration, we examined the detailed expression/localization patterns of Baf60c in both mice and axolotls. In the mouse heart development, Baf60c was highly expressed in the entire heart at the early stages, but gradually downregulated at the postnatal stages. During heart regeneration in neonatal mice and axolotls, Baf60c expression was strongly upregulated after resection. Interestingly, the timing of Baf60c upregulation after resection was consistent with the temporal dynamics of cardiomyocyte proliferation. Moreover, knockdown of Baf60c downregulated proliferation of neonatal mouse cardiomyocytes. These data suggested that Baf60c plays an important role in cardiomyocyte proliferation in heart development and regeneration. This is the first study indicating that Baf60c contributes to the heart regeneration in vertebrates.
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Affiliation(s)
- Ryo Nakamura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, 113-0033, Japan.,Division of Cardiovascular Regeneration, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo, Tokyo, 113-0032, Japan
| | - Kazuko Koshiba-Takeuchi
- Division of Cardiovascular Regeneration, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo, Tokyo, 113-0032, Japan
| | - Megumi Tsuchiya
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan
| | - Mizuyo Kojima
- Division of Cardiovascular Regeneration, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo, Tokyo, 113-0032, Japan
| | - Asuka Miyazawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, 113-0033, Japan.,Division of Cardiovascular Regeneration, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo, Tokyo, 113-0032, Japan
| | - Kohei Ito
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, 113-0033, Japan.,Division of Cardiovascular Regeneration, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo, Tokyo, 113-0032, Japan
| | - Hidesato Ogawa
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, 651-2492, Japan
| | - Jun K Takeuchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, 113-0033, Japan.,Division of Cardiovascular Regeneration, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo, Tokyo, 113-0032, Japan
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7
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Actin, actin-binding proteins, and actin-related proteins in the nucleus. Histochem Cell Biol 2016; 145:373-88. [PMID: 26847179 DOI: 10.1007/s00418-015-1400-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2015] [Indexed: 10/25/2022]
Abstract
Extensive research in the past decade has significantly broadened our view about the role actin plays in the life of the cell and added novel aspects to actin research. One of these new aspects is the discovery of the existence of nuclear actin which became evident only recently. Nuclear activities including transcriptional activation in the case of all three RNA polymerases, editing and nuclear export of mRNAs, and chromatin remodeling all depend on actin. It also became clear that there is a fine-tuned equilibrium between cytoplasmic and nuclear actin pools and that this balance is ensured by an export-import system dedicated to actin. After over half a century of research on conventional actin and its organizing partners in the cytoplasm, it was also an unexpected finding that the nucleus contains more than 30 actin-binding proteins and new classes of actin-related proteins which are not able to form filaments but had evolved nuclear-specific functions. The actin-binding and actin-related proteins in the nucleus have been linked to RNA transcription and processing, nuclear transport, and chromatin remodeling. In this paper, we attempt to provide an overview of the wide range of information that is now available about actin, actin-binding, and actin-related proteins in the nucleus.
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8
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Hsu CH, Chiang AWT, Hwang MJ, Liao BY. Proteins with Highly Evolvable Domain Architectures Are Nonessential but Highly Retained. Mol Biol Evol 2016; 33:1219-30. [DOI: 10.1093/molbev/msw006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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9
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Actin, actin-related proteins and profilin in diatoms: A comparative genomic analysis. Mar Genomics 2015; 23:133-42. [DOI: 10.1016/j.margen.2015.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 06/30/2015] [Accepted: 07/02/2015] [Indexed: 12/24/2022]
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10
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Sadhukhan S, Sarkar K, Taylor M, Candotti F, Vyas YM. Nuclear role of WASp in gene transcription is uncoupled from its ARP2/3-dependent cytoplasmic role in actin polymerization. THE JOURNAL OF IMMUNOLOGY 2014; 193:150-60. [PMID: 24872192 DOI: 10.4049/jimmunol.1302923] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Defects in Wiskott-Aldrich Syndrome protein (WASp) underlie development of WAS, an X-linked immunodeficiency and autoimmunity disorder of childhood. Nucleation-promoting factors (NPFs) of the WASp family generate F-actin in the cytosol via the VCA (verprolin-homology, cofilin-homology, and acidic) domain and support RNA polymerase II-dependent transcription in the nucleus. Whether nuclear-WASp requires the integration of its actin-related protein (ARP)2/3-dependent cytoplasmic function to reprogram gene transcription, however, remains unresolved. Using the model of human TH cell differentiation, we find that WASp has a functional nuclear localizing and nuclear exit sequences, and accordingly, its effects on transcription are controlled mainly at the level of its nuclear entry and exit via the nuclear pore. Human WASp does not use its VCA-dependent, ARP2/3-driven, cytoplasmic effector mechanisms to support histone H3K4 methyltransferase activity in the nucleus of TH1-skewed cells. Accordingly, an isolated deficiency of nuclear-WASp is sufficient to impair the transcriptional reprogramming of TBX21 and IFNG promoters in TH1-skewed cells, whereas an isolated deficiency of cytosolic-WASp does not impair this process. In contrast, nuclear presence of WASp in TH2-skewed cells is small, and its loss does not impair transcriptional reprogramming of GATA3 and IL4 promoters. Our study unveils an ARP2/3:VCA-independent function of nuclear-WASp in TH1 gene activation that is uncoupled from its cytoplasmic role in actin polymerization.
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Affiliation(s)
- Sanjoy Sadhukhan
- Division of Pediatric Hematology-Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15213
| | - Koustav Sarkar
- Division of Pediatric Hematology-Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15213; Division of Pediatric Hematology-Oncology, University of Iowa Children's Hospital, Iowa City, IA 52242; and
| | - Matthew Taylor
- Division of Pediatric Hematology-Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15213
| | - Fabio Candotti
- Genetics and Molecular Biology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892
| | - Yatin M Vyas
- Division of Pediatric Hematology-Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15213; Division of Pediatric Hematology-Oncology, University of Iowa Children's Hospital, Iowa City, IA 52242; and
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11
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Abstract
Arp5 suppresses myocardin activity through both direct binding to myocardin and binding to SRF to prevent transcriptional activation of myogenic genes by the myocardin–SRF complex. Myocardin (Myocd) and Myocd-related transcription factors (MRTFs) are robust coactivators of serum response factor (SRF). RPEL motifs are monomeric globular actin (G-actin) binding elements that regulate MRTF localization and activity. However, the function of the RPEL motif in Myocd is largely unknown because of its low affinity for G-actin. Here, we demonstrated that the Myocd RPEL motif bound to actin-related protein 5 (Arp5) instead of conventional actin, resulting in a significant suppression of Myocd activity. In addition, Arp5 bound to a DNA binding domain of SRF via its C-terminal sequence and prevented the association of the Myocd–SRF complex with the promoter regions of smooth muscle genes. Well-differentiated smooth muscle cells mainly expressed a specific splicing variant of arp5; therefore, the protein level of Arp5 was markedly reduced by partial messenger RNA decay and translational suppression. In dedifferentiated smooth muscle cells, Arp5 knockdown restored the differentiated phenotype via Myocd activation. Thus, Arp5 is a key regulator of Myocd activity.
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Affiliation(s)
- Tsuyoshi Morita
- Department of Neuroscience, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
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12
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Nashima K, Takahashi H, Nakazono M, Shimizu T, Nishitani C, Yamamoto T, Itai A, Isuzugawa K, Hanada T, Takashina T, Kato M, Matsumoto S, Oikawa A, Shiratake K. Transcriptome Analysis of Giant Pear Fruit with Fruit-specific DNA Reduplication on a Mutant Branch. ACTA ACUST UNITED AC 2013. [DOI: 10.2503/jjshs1.82.301] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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Maruyama EO, Hori T, Tanabe H, Kitamura H, Matsuda R, Tone S, Hozak P, Habermann FA, von Hase J, Cremer C, Fukagawa T, Harata M. The actin family member Arp6 and the histone variant H2A.Z are required for spatial positioning of chromatin in chicken cell nuclei. J Cell Sci 2012; 125:3739-43. [PMID: 22573822 DOI: 10.1242/jcs.103903] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The spatial organization of chromatin in the nucleus contributes to genome function and is altered during the differentiation of normal and tumorigenic cells. Although nuclear actin-related proteins (Arps) have roles in the local alteration of chromatin structure, it is unclear whether they are involved in the spatial positioning of chromatin. In the interphase nucleus of vertebrate cells, gene-dense and gene-poor chromosome territories (CTs) are located in the center and periphery, respectively. We analyzed chicken DT40 cells in which Arp6 had been knocked out conditionally, and showed that the radial distribution of CTs was impaired in these knockout cells. Arp6 is an essential component of the SRCAP chromatin remodeling complex, which deposits the histone variant H2A.Z into chromatin. The redistribution of CTs was also observed in H2A.Z-deficient cells for gene-rich microchromosomes, but to lesser extent for gene-poor macrochromosomes. These results indicate that Arp6 and H2A.Z contribute to the radial distribution of CTs through different mechanisms. Microarray analysis suggested that the localization of chromatin to the nuclear periphery per se is insufficient for the repression of most genes.
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Affiliation(s)
- Eri Ohfuchi Maruyama
- Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University, Tsutsumidori-Amamiyamachi 1-1, Aoba-ku, Sendai 981-8555, Japan
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14
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Nuclear actin-related protein is required for chromosome segregation in Toxoplasma gondii. Mol Biochem Parasitol 2011; 181:7-16. [PMID: 21963440 DOI: 10.1016/j.molbiopara.2011.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Revised: 09/10/2011] [Accepted: 09/15/2011] [Indexed: 12/30/2022]
Abstract
Apicomplexa parasites use complex cell cycles to replicate that are not well understood mechanistically. We have established a robust forward genetic strategy to identify the essential components of parasite cell division. Here we describe a novel temperature sensitive Toxoplasma strain, mutant 13-20C2, which growth arrests due to a defect in mitosis. The primary phenotype is the mis-segregation of duplicated chromosomes with chromosome loss during nuclear division. This defect is conditional-lethal with respect to temperature, although relatively mild in regard to the preservation of the major microtubule organizing centers. Despite severe DNA loss many of the physical structures associated with daughter budding and the assembly of invasion structures formed and operated normally at the non-permissive temperature before completely arresting. These results suggest there are coordinating mechanisms that govern the timing of these events in the parasite cell cycle. The defect in mutant 13-20C2 was mapped by genetic complementation to Toxoplasma chromosome III and to a specific mutation in the gene encoding an ortholog of nuclear actin-related protein 4. A change in a conserved isoleucine to threonine in the helical structure of this nuclear actin related protein leads to protein instability and cellular mis-localization at the higher temperature. Given the age of this protist family, the results indicate a key role for nuclear actin-related proteins in chromosome segregation was established very early in the evolution of eukaryotes.
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15
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Boëda B, Knowles PP, Briggs DC, Murray-Rust J, Soriano E, Garvalov BK, McDonald NQ, Way M. Molecular recognition of the Tes LIM2-3 domains by the actin-related protein Arp7A. J Biol Chem 2011; 286:11543-54. [PMID: 21278383 PMCID: PMC3064208 DOI: 10.1074/jbc.m110.171264] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 12/15/2010] [Indexed: 11/06/2022] Open
Abstract
Actin-related proteins (Arps) are a highly conserved family of proteins that have extensive sequence and structural similarity to actin. All characterized Arps are components of large multimeric complexes associated with chromatin or the cytoskeleton. In addition, the human genome encodes five conserved but largely uncharacterized "orphan" Arps, which appear to be mostly testis-specific. Here we show that Arp7A, which has 43% sequence identity with β-actin, forms a complex with the cytoskeletal proteins Tes and Mena in the subacrosomal layer of round spermatids. The N-terminal 65-residue extension to the actin-like fold of Arp7A interacts directly with Tes. The crystal structure of the 1-65(Arp7A)·LIM2-3(Tes)·EVH1(Mena) complex reveals that residues 28-49 of Arp7A contact the LIM2-3 domains of Tes. Two alanine residues from Arp7A that occupy equivalent apolar pockets in both LIM domains as well as an intervening GPAK linker that binds the LIM2-3 junction are critical for the Arp7A-Tes interaction. Equivalent occupied apolar pockets are also seen in the tandem LIM domain structures of LMO4 and Lhx3 bound to unrelated ligands. Our results indicate that apolar pocket interactions are a common feature of tandem LIM domain interactions, but ligand specificity is principally determined by the linker sequence.
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Affiliation(s)
- Batiste Boëda
- From the Cell Motility and
- the Cell Polarity and Migration Group, CNRS 2582, Institut Pasteur, 75724 Paris, France, and
| | - Phillip P. Knowles
- Structural Biology Laboratories, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, United Kingdom
| | - David C. Briggs
- Structural Biology Laboratories, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, United Kingdom
- the Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Judith Murray-Rust
- Structural Biology Laboratories, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, United Kingdom
| | - Erika Soriano
- Structural Biology Laboratories, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, United Kingdom
| | - Boyan K. Garvalov
- the Institute of Neuropathology, Justus Liebig University, Aulweg 123, 35392 Giessen, Germany
| | - Neil Q. McDonald
- Structural Biology Laboratories, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, United Kingdom
- the Institute of Structural and Molecular Biology, University College London and Birkbeck College, Malet Street, London WC1E 7HX, United Kingdom
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16
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Costas C, Desvoyes B, Gutierrez C. A chromatin perspective of plant cell cycle progression. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1809:379-87. [PMID: 21453801 DOI: 10.1016/j.bbagrm.2011.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 03/18/2011] [Accepted: 03/23/2011] [Indexed: 12/27/2022]
Abstract
The finely regulated series of events that span from the birth of a cell to the production of two new born cells encompass the cell cycle. Cell cycle progression occurs in a unidirectional manner and requires passing through a number of stages in response to cellular, developmental and environmental cues. In addition to these signaling cascades, transcriptional regulation plays a major role and acts coordinately with genome duplication during S-phase and chromosome segregation during mitosis. In this context, chromatin is revealing as a highly dynamic and major player in cell cycle regulation not only owing to the changes that occur as a consequence of cell cycle progression but also because some specific chromatin modifications are crucial to move across the cell cycle. These are particularly relevant for controlling transcriptional activation and repression as well as initiation of DNA replication and chromosome compaction. As a consequence the epigenetic landscape of a proliferating cell is very complex throughout the cell cycle. These aspects of chromatin dynamics together with the impact of epigenetic modifications on cell proliferation will be discussed in this article. This article is part of a Special Issue entitled: Epigenetic Control of cellular and developmental processes in plants.
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Affiliation(s)
- Celina Costas
- Centro de Biologia Molecukar Severo Ochoa, Madrid, Spain
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17
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Kandasamy MK, McKinney EC, Meagher RB. Differential sublocalization of actin variants within the nucleus. Cytoskeleton (Hoboken) 2011; 67:729-43. [PMID: 20862689 DOI: 10.1002/cm.20484] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Conventional actin has been implicated in various nuclear processes including chromatin remodeling, transcription, nuclear transport, and overall nuclear structure. Moreover, actin has been identified as a component of several chromatin remodeling complexes present in the nucleus. In animal cells, nuclear actin exists as a dynamic equilibrium of monomers and polymers. Actin-binding proteins (ABPs) such as ADF/cofilin and profilin play a role in actin import and export, respectively. However, very little is known about the localization and roles of nuclear actin in plants. In multicellular plants and animals, actin is comprised of an ancient and divergent family of protein variants. Here, we have investigated the presence and differential localization of two ancient subclasses of actin in isolated Arabidopsis nuclei. Although the subclass 1 variants ACT2 and ACT8 and subclass 2 variant ACT7 were found distributed throughout the nucleoplasm, ACT7 was often found more concentrated in nuclear speckles than subclass 1 variants. The nuclei from the act2-1/act8-2 double null mutant and the act7-5 null mutant lacked their corresponding actin variants. In addition, serial sectioning of several independent nuclei revealed that ACT7 was notably more abundant in the nucleolus than the subclass 1 actins. Profilin and ADF proteins were also found in significant levels in plant nuclei. The possible functions of differentially localized nuclear actin variants are discussed.
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Affiliation(s)
- Muthugapatti K Kandasamy
- Department of Genetics, Davison Life Sciences Complex, University of Georgia, Athens, Georgia 30602, USA
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Oma Y, Harata M. Actin-related proteins localized in the nucleus: from discovery to novel roles in nuclear organization. Nucleus 2011; 2:38-46. [PMID: 21647298 PMCID: PMC3104808 DOI: 10.4161/nucl.2.1.14510] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 12/15/2010] [Accepted: 12/17/2010] [Indexed: 12/18/2022] Open
Abstract
The actin family consists of conventional actin and actin-related proteins (ARPs), and the members show moderate similarity and share the same basal structure. Following the finding of various ARPs in the cytoplasm in the 1990s, multiple subfamilies that are localized predominantly in the nucleus were identified. Consistent with these cytological observations, subsequent biochemical analyses revealed the involvement of the nuclear ARPs in ATP-dependent chromatin-remodeling and histone acetyltransferase complexes. In addition to their contribution to chromatin remodeling, recent studies have shown that nuclear ARPs have roles in the organization of the nucleus that are independent of the activity of the above-mentioned complexes. Therefore, nuclear ARPs are recognized as novel key regulators of genome function, and affect not only the remodeling of chromatin but also the spatial arrangement and dynamics of chromatin within the nucleus.
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Affiliation(s)
- Yukako Oma
- Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
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Meagher RB. The evolution of epitype. THE PLANT CELL 2010; 22:1658-66. [PMID: 20551346 PMCID: PMC2910975 DOI: 10.1105/tpc.110.075481] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 05/03/2010] [Accepted: 05/26/2010] [Indexed: 05/08/2023]
Abstract
The epitype of a single gene or entire genome is determined by cis-linked differences in chromatin structure. I explore the hypothesis that "epitype and associated phenotypes evolve by gene duplication, divergence, and subfunctionalization" parallel to models for the evolution of genotype. This hypothesis is dissected by considering the relationship between epigenetic control and phenotype, the phylogenetic evidence that epitype evolves from ancestral genes following gene duplication, and the possible evolutionary rates of change for different epitypes. Initial supporting arguments for this hypothesis are discussed based on conserved patterns of nucleosome phasing, DNA methylation, and histone variant H2AZ deposition that appear to contribute to the inheritance of epitype in plants and animals. However, patterns of histone modification in recent segmental chromosome duplications are not well conserved. A continued experimental examination of the link between gene phylogeny and epitype and the evolution of epigenetically determined phenotypes is needed to further explore this hypothesis.
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Affiliation(s)
- Richard B Meagher
- Department of Genetics, University of Georgia, Athens, Georgia 30602, USA.
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Castano E, Philimonenko VV, Kahle M, Fukalová J, Kalendová A, Yildirim S, Dzijak R, Dingová-Krásna H, Hozák P. Actin complexes in the cell nucleus: new stones in an old field. Histochem Cell Biol 2010; 133:607-26. [PMID: 20443021 DOI: 10.1007/s00418-010-0701-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2010] [Indexed: 01/13/2023]
Abstract
Actin is a well-known protein that has shown a myriad of activities in the cytoplasm. However, recent findings of actin involvement in nuclear processes are overwhelming. Actin complexes in the nucleus range from very dynamic chromatin-remodeling complexes to structural elements of the matrix with single partners known as actin-binding proteins (ABPs). This review summarizes the recent findings of actin-containing complexes in the nucleus. Particular attention is given to key processes like chromatin remodeling, transcription, DNA replication, nucleocytoplasmic transport and to actin roles in nuclear architecture. Understanding the mechanisms involving ABPs will definitely lead us to the principles of the regulation of gene expression performed via concerting nuclear and cytoplasmic processes.
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Affiliation(s)
- E Castano
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the ASCR, Prague, Czech Republic
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Dion V, Shimada K, Gasser SM. Actin-related proteins in the nucleus: life beyond chromatin remodelers. Curr Opin Cell Biol 2010; 22:383-91. [PMID: 20303249 DOI: 10.1016/j.ceb.2010.02.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 02/24/2010] [Accepted: 02/24/2010] [Indexed: 12/18/2022]
Abstract
Since their discovery in the mid-1990s, nuclear actin-related proteins (ARPs) have gained attention for their roles as structural components of ATP-dependent chromatin-remodeling complexes. These remodelers can move nucleosomes along the DNA, evict them from chromatin, and exchange histone variants to alter chromatin states locally. Chromatin-remodeling facilitates DNA-templated processes such as transcription regulation, DNA replication, and repair. Consistent with a role for ARPs in shaping chromatin structure, recent genetic studies show that they affect developmental and cell-type specific transcriptional programming. Here, we focus on recent results that suggest a specific contribution of ARPs to long-range interactions in the nucleus, and review evidence indicating that some ARPs may act independently of chromatin-remodeling machines.
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Affiliation(s)
- Vincent Dion
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
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Kandasamy MK, McKinney EC, Deal RB, Smith AP, Meagher RB. Arabidopsis actin-related protein ARP5 in multicellular development and DNA repair. Dev Biol 2009; 335:22-32. [PMID: 19679120 PMCID: PMC2778271 DOI: 10.1016/j.ydbio.2009.08.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 07/31/2009] [Accepted: 08/04/2009] [Indexed: 10/20/2022]
Abstract
Actin-related protein 5 (ARP5) is a conserved subunit of the INO80 chromatin-remodeling complex in yeast and mammals. We have characterized the expression and subcellular distribution of Arabidopsis thaliana ARP5 and explored its role in the epigenetic control of multicellular development and DNA repair. ARP5-specific monoclonal antibodies localized ARP5 protein to the nucleoplasm of interphase cells in Arabidopsis and Nicotiana tabacum. ARP5 promoter-reporter fusions and the ARP5 protein are ubiquitously expressed. A null mutant and a severe knockdown allele produced moderately dwarfed plants with all organs smaller than the wild type. The small and slightly deformed organs such as leaves and hypocotyls were composed of small-sized cells. The ratio of leaf stomata to epidermal cells was high in the mutant, which also exhibited a delayed stomatal development compared with the wild type. Mutant plants were hypersensitive to DNA-damaging reagents including hydroxyurea, methylmethane sulfonate, and bleocin, demonstrating a role for ARP5 in DNA repair. Interestingly, the hypersensitivity phenotype of ARP5 null allele arp5-1 is stronger than the severe knockdown allele arp5-2. Moreover, a wild-type transgene fully complemented all developmental and DNA repair mutant phenotypes. Despite the common participation of both ARP4 and ARP5 in the INO80 complex, ARP4- and ARP5-deficient plants displayed only a small subset of common phenotypes and each displayed novel phenotypes, suggesting that in Arabidopsis they have both shared and unique functions.
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Affiliation(s)
| | - Elizabeth C. McKinney
- Department of Genetics, Davison Life Sciences Complex, University of Georgia, Athens, GA 30602, USA
| | - Roger B. Deal
- Department of Genetics, Davison Life Sciences Complex, University of Georgia, Athens, GA 30602, USA
| | - Aaron P. Smith
- Department of Genetics, Davison Life Sciences Complex, University of Georgia, Athens, GA 30602, USA
| | - Richard B. Meagher
- Department of Genetics, Davison Life Sciences Complex, University of Georgia, Athens, GA 30602, USA
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