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Wasąg P, Suwińska A, Richert A, Lenartowska M, Lenartowski R. Plant-specific calreticulin is localized in the nuclei of highly specialized cells in the pistil-new observations for an old hypothesis. PROTOPLASMA 2024:10.1007/s00709-024-01961-y. [PMID: 38849663 DOI: 10.1007/s00709-024-01961-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 05/31/2024] [Indexed: 06/09/2024]
Abstract
One of the first cellular locations of the calreticulin (CRT) chaperone in eukaryotic cells, apart from its obvious localization in the endoplasmic reticulum (ER), was the cell nucleus (Opas et al. 1991). The presence of CRT has been detected inside the nucleus and in the nuclear envelope of animal and plant cells, and a putative nuclear localization signal (NLS) in the CRT amino acid sequence has been mapped in several animal and plant species. Over the last 30 years, other localization sites of this protein outside the ER and cell nucleus have also been discovered, suggesting that CRT is a multifunctional Ca2+-binding protein widely found in various cell types. In our previous studies focusing on plant developmental biology, we have demonstrated the presence of CRT inside and outside the ER in highly specialized plant cells, as well as the possibility of CRT localization in the cell nucleus. In this paper, we present a detailed analysis of immunocytochemical localization of CRT inside nuclei of the pistil transmission tract somatic cells before and after pollination. We show a similar pattern of the nuclear CRT localization in relation to exchangeable Ca2+ for two selected species of angiosperms, dicotyledonous Petunia and monocot Haemanthus, that differ in anatomical structure of the pistil and discuss the potential role of CRT in the cell nucleus.
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Affiliation(s)
- Piotr Wasąg
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland.
| | - Anna Suwińska
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Anna Richert
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Marta Lenartowska
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Robert Lenartowski
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Toruń, Poland
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Acosta-Cárdenas J, Jiménez-García LF, Cruz-Gómez SDJ, Mendoza-von der Borch AP, Segura-Valdez MDL. Microscopic Analysis of Nuclear Speckles in a Viviparous Reptile. Int J Mol Sci 2024; 25:5281. [PMID: 38791320 PMCID: PMC11120696 DOI: 10.3390/ijms25105281] [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: 04/10/2024] [Revised: 05/10/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
Nuclear speckles are compartments enriched in splicing factors present in the nucleoplasm of eucaryote cells. Speckles have been studied in mammalian culture and tissue cells, as well as in some non-mammalian vertebrate cells and invertebrate oocytes. In mammals, their morphology is linked to the transcriptional and splicing activities of the cell through a recruitment mechanism. In rats, speckle morphology depends on the hormonal cycle. In the present work, we explore whether a similar situation is also present in non-mammalian cells during the reproductive cycle. We studied the speckled pattern in several tissues of a viviparous reptile, the lizard Sceloporus torquatus, during two different stages of reproduction. We used immunofluorescence staining against splicing factors in hepatocytes and oviduct epithelium cells and fluorescence and confocal microscopy, as well as ultrastructural immunolocalization and EDTA contrast in Transmission Electron Microscopy. The distribution of splicing factors in the nucleoplasm of oviductal cells and hepatocytes coincides with the nuclear-speckled pattern described in mammals. Ultrastructurally, those cell types display Interchromatin Granule Clusters and Perichromatin Fibers. In addition, the morphology of speckles varies in oviduct cells at the two stages of the reproductive cycle analyzed, paralleling the phenomenon observed in the rat. The results show that the morphology of speckles in reptile cells depends upon the reproductive stage as it occurs in mammals.
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Affiliation(s)
- Jeniffer Acosta-Cárdenas
- Laboratorio de Nanobiología Celular, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México—UNAM, Mexico City 04510, Mexico; (J.A.-C.); (L.F.J.-G.); (S.d.J.C.-G.); (A.P.M.-v.d.B.)
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Luis Felipe Jiménez-García
- Laboratorio de Nanobiología Celular, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México—UNAM, Mexico City 04510, Mexico; (J.A.-C.); (L.F.J.-G.); (S.d.J.C.-G.); (A.P.M.-v.d.B.)
| | - Sarai de Jesús Cruz-Gómez
- Laboratorio de Nanobiología Celular, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México—UNAM, Mexico City 04510, Mexico; (J.A.-C.); (L.F.J.-G.); (S.d.J.C.-G.); (A.P.M.-v.d.B.)
| | - Ana Paulina Mendoza-von der Borch
- Laboratorio de Nanobiología Celular, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México—UNAM, Mexico City 04510, Mexico; (J.A.-C.); (L.F.J.-G.); (S.d.J.C.-G.); (A.P.M.-v.d.B.)
| | - María de Lourdes Segura-Valdez
- Laboratorio de Nanobiología Celular, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México—UNAM, Mexico City 04510, Mexico; (J.A.-C.); (L.F.J.-G.); (S.d.J.C.-G.); (A.P.M.-v.d.B.)
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Inguscio CR, Lacavalla MA, Cisterna B, Zancanaro C, Malatesta M. Physical Training Chronically Stimulates the Motor Neuron Cell Nucleus in the Ts65Dn Mouse, a Model of Down Syndrome. Cells 2023; 12:1488. [PMID: 37296609 PMCID: PMC10252427 DOI: 10.3390/cells12111488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/20/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
Down syndrome (DS) is a genetically-based disease based on the trisomy of chromosome 21 (Hsa21). DS is characterized by intellectual disability in association with several pathological traits among which early aging and altered motor coordination are prominent. Physical training or passive exercise were found to be useful in counteracting motor impairment in DS subjects. In this study we used the Ts65Dn mouse, a widely accepted animal model of DS, to investigate the ultrastructural architecture of the medullary motor neuron cell nucleus taken as marker of the cell functional state. Using transmission electron microscopy, ultrastructural morphometry, and immunocytochemistry we carried out a detailed investigation of possible trisomy-related alteration(s) of nuclear constituents, which are known to vary their amount and distribution as a function of nuclear activity, as well as the effect of adapted physical training upon them. Results demonstrated that trisomy per se affects nuclear constituents to a limited extent; however, adapted physical training is able to chronically stimulate pre-mRNA transcription and processing activity in motor neuron nuclei of trisomic mice, although to a lesser extent than in their euploid mates. These findings are a step towards understanding the mechanisms underlying the positive effect of physical activity in DS.
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Affiliation(s)
| | | | | | - Carlo Zancanaro
- Department of Neurosciences, Biomedicine and Movement Sciences, Anatomy and Histology Section, University of Verona, Strada Le Grazie 8, I-37134 Verona, Italy; (C.R.I.); (M.A.L.); (B.C.); (M.M.)
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Suwińska A, Wasąg P, Bednarska-Kozakiewicz E, Lenartowska M, Lenartowski R. Calreticulin expression and localization in relation to exchangeable Ca 2+ during pollen development in Petunia. BMC PLANT BIOLOGY 2022; 22:24. [PMID: 34998378 PMCID: PMC8742381 DOI: 10.1186/s12870-021-03409-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND Pollen development in the anther in angiosperms depends on complicated cellular interactions associated with the expression of gametophytic and sporophytic genes which control fundamental processes during microsporo/gametogenesis, such as exo/endocytosis, intracellular transport, cell signaling, chromatin remodeling, and cell division. Most if not all of these cellular processes depend of local concentration of calcium ions (Ca2+). Work from our laboratory and others provide evidence that calreticulin (CRT), a prominent Ca2+-binding/buffering protein in the endoplasmic reticulum (ER) of eukaryotic cells, may be involved in pollen formation and function. Here, we show for the first time the expression pattern of the PhCRT1 gene and CRT accumulation in relation to exchangeable Ca2+ in Petunia hybrida developing anther, and discuss probable roles for this protein in the male gametophyte development. RESULTS Using northern hybridization, western blot analysis, fluorescent in situ hybridization (FISH), immunocytochemistry, and potassium antimonate precipitation, we report that PhCRT1 is highly expressed in the anther and localization pattern of the CRT protein correlates with loosely bound (exchangeable) Ca2+ during the successive stages of microsporo/gametogenesis. We confirmed a permanent presence of both CRT and exchangeable Ca2+ in the germ line and tapetal cells, where these factors preferentially localized to the ER which is known to be the most effective intracellular Ca2+ store in eukaryotic cells. In addition, our immunoblots revealed a gradual increase in CRT level from the microsporocyte stage through the meiosis and the highest CRT level at the microspore stage, when both microspores and tapetal cells show extremely high secretory activity correlated with the biogenesis of the sporoderm. CONCLUSION Our present data provide support for a key role of CRT in developing anther of angiosperms - regulation of Ca2+ homeostasis during pollen grains formation. This Ca2+-buffering chaperone seems to be essential for pollen development and maturation since a high rate of protein synthesis and protein folding within the ER as well as intracellular Ca2+ homeostasis are strictly required during the multi-step process of pollen development.
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Affiliation(s)
- Anna Suwińska
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Piotr Wasąg
- Department of Biochemistry and Cell Biology, Faculty of Biological Sciences, Kazimierz Wielki University, Bydgoszcz, Poland
| | - Elżbieta Bednarska-Kozakiewicz
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Marta Lenartowska
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Robert Lenartowski
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland.
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Toruń, Poland.
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Swamy H, Glading AJ. Is Location Everything? Regulation of the Endothelial CCM Signaling Complex. Front Cardiovasc Med 2022; 9:954780. [PMID: 35898265 PMCID: PMC9309484 DOI: 10.3389/fcvm.2022.954780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 06/17/2022] [Indexed: 11/13/2022] Open
Abstract
Recent advances have steadily increased the number of proteins and pathways known to be involved in the development of cerebral cavernous malformation (CCM). Our ability to synthesize this information into a cohesive and accurate signaling model is limited, however, by significant gaps in our knowledge of how the core CCM proteins, whose loss of function drives development of CCM, are regulated. Here, we review what is known about the regulation of the three core CCM proteins, the scaffolds KRIT1, CCM2, and CCM3, with an emphasis on binding interactions and subcellular location, which frequently control scaffolding protein function. We highlight recent work that challenges the current model of CCM complex signaling and provide recommendations for future studies needed to address the large number of outstanding questions.
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Affiliation(s)
- Harsha Swamy
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, United States
| | - Angela J Glading
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, United States
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Lacavalla MA, Cisterna B, Zancanaro C, Malatesta M. Ultrastructural immunocytochemistry shows impairment of RNA pathways in skeletal muscle nuclei of old mice: A link to sarcopenia? Eur J Histochem 2021; 65:3229. [PMID: 33764019 PMCID: PMC8033527 DOI: 10.4081/ejh.2021.3229] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 03/15/2021] [Indexed: 12/12/2022] Open
Abstract
During aging, skeletal muscle is affected by sarcopenia, a progressive decline in muscle mass, strength and endurance that leads to loss of function and disability. Cell nucleus dysfunction is a possible factor contributing to sarcopenia because aging-associated alterations in mRNA and rRNA transcription/maturation machinery have been shown in several cell types including muscle cells. In this study, the distribution and density of key molecular factors involved in RNA pathways namely, nuclear actin (a motor protein and regulator of RNA transcription), 5-methyl cytosine (an epigenetic regulator of gene transcription), and ribonuclease A (an RNA degrading enzyme) were compared in different nuclear compartments of late adult and old mice myonuclei by means of ultrastructural immunocytochemistry. In all nuclear compartments, an age-related decrease of nuclear actin suggested altered chromatin structuring and impaired nucleus-to-cytoplasm transport of both mRNA and ribosomal subunits, while a decrease of 5-methyl cytosine and ribonuclease A in the nucleoli of old mice indicated an age-dependent loss of rRNA genes. These findings provide novel experimental evidence that, in the aging skeletal muscle, nuclear RNA pathways undergo impairment, likely hindering protein synthesis and contributing to the onset and progression of sarcopenia.
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Affiliation(s)
| | - Barbara Cisterna
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona.
| | - Carlo Zancanaro
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona.
| | - Manuela Malatesta
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona.
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Malatesta M, Costanzo M, Cisterna B, Zancanaro C. Satellite Cells in Skeletal Muscle of the Hibernating Dormouse, a Natural Model of Quiescence and Re-Activation: Focus on the Cell Nucleus. Cells 2020; 9:cells9041050. [PMID: 32340154 PMCID: PMC7226265 DOI: 10.3390/cells9041050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/15/2020] [Accepted: 04/21/2020] [Indexed: 02/06/2023] Open
Abstract
Satellite cells (SCs) participate in skeletal muscle plasticity/regeneration. Activation of SCs implies that nuclear changes underpin a new functional status. In hibernating mammals, periods of reduced metabolic activity alternate with arousals and resumption of bodily functions, thereby leading to repeated cell deactivation and reactivation. In hibernation, muscle fibers are preserved despite long periods of immobilization. The structural and functional characteristics of SC nuclei during hibernation have not been investigated yet. Using ultrastructural and immunocytochemical analysis, we found that the SCs of the hibernating edible dormouse, Glis glis, did not show apoptosis or necrosis. Moreover, their nuclei were typical of quiescent cells, showing similar amounts and distributions of heterochromatin, pre-mRNA transcription and processing factors, as well as paired box protein 7 (Pax7) and the myogenic differentiation transcription factor D (MyoD), as in euthermia. However, the finding of accumulated perichromatin granules (i.e., sites of storage/transport of spliced pre-mRNA) in SC nuclei of hibernating dormice suggested slowing down of the nucleus-to-cytoplasm transport. We conclude that during hibernation, SC nuclei maintain similar transcription and splicing activity as in euthermia, indicating an unmodified status during immobilization and hypometabolism. Skeletal muscle preservation during hibernation is presumably not due to SC activation, but rather to the maintenance of some functional activity in myofibers that is able to counteract muscle wasting.
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Affiliation(s)
- Manuela Malatesta
- Anatomy and Histology Section, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie, 8 I-37134 Verona, Italy; (M.M.); (M.C.); (C.Z.)
| | - Manuela Costanzo
- Anatomy and Histology Section, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie, 8 I-37134 Verona, Italy; (M.M.); (M.C.); (C.Z.)
| | - Barbara Cisterna
- Anatomy and Histology Section, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie, 8 I-37134 Verona, Italy; (M.M.); (M.C.); (C.Z.)
- Correspondence:
| | - Carlo Zancanaro
- Anatomy and Histology Section, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie, 8 I-37134 Verona, Italy; (M.M.); (M.C.); (C.Z.)
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Castillo-Iglesias MS, Berciano MT, Narcis JO, Val-Bernal JF, Rodriguez-Rey JC, Tapia O, Lafarga M. Reorganization of the nuclear compartments involved in transcription and RNA processing in myonuclei of type I spinal muscular atrophy. Histochem Cell Biol 2019; 152:227-237. [PMID: 31183542 DOI: 10.1007/s00418-019-01792-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2019] [Indexed: 01/01/2023]
Abstract
Type I spinal muscular atrophy (SMA) is an autosomal recessive disorder caused by the loss or mutation of the survival motor neuron 1 (SMN1) gene. The reduction in SMN protein levels in SMA leads to the degeneration of motor neurons and muscular atrophy. In this study, we analyzed the nuclear reorganization in human skeletal myofibers from a type I SMA patient carrying a deletion of exons 7 and 8 in the SMN1 gene and two SMN2 gene copies and showing reduced SMN protein levels in the muscle compared with those in control samples. The morphometric analysis of myofiber size revealed the coexistence of atrophic and hypertrophic myofibers in SMA samples. Compared with controls, both nuclear size and the nuclear shape factor were significantly reduced in SMA myonuclei. Nuclear reorganization in SMA myonuclei was characterized by extensive heterochromatinization, the aggregation of splicing factors in large interchromatin granule clusters, and nucleolar alterations with the accumulation of the granular component and a loss of fibrillar center/dense fibrillar component units. These nuclear alterations reflect a severe perturbation of global pre-mRNA transcription and splicing, as well as nucleolar dysfunction, in SMA myofibers. Moreover, the finding of similar nuclear reorganization in both atrophic and hypetrophic myofibers provides additional support that the SMN deficiency in SMA patients may primarily affect the skeletal myofibers.
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Affiliation(s)
- María S Castillo-Iglesias
- Departamento de Anatomía y Biología Celular and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", Universidad de Cantabria-IDIVAL, Avd. Cardenal Herrera Oria s/n, 39011, Santander, Spain
| | - María T Berciano
- Departamento de Biología Molecular, Universidad de Cantabria-IDIVAL, Santander, Spain
| | - J Oriol Narcis
- Departamento de Anatomía y Biología Celular and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", Universidad de Cantabria-IDIVAL, Avd. Cardenal Herrera Oria s/n, 39011, Santander, Spain
| | - J Fernando Val-Bernal
- Unidad de Patología, Departamento de Ciencias Médicas y Quirúrgicas, Universidad de Cantabria-IDIVAL, Santander, Spain
| | - José C Rodriguez-Rey
- Departamento de Biología Molecular, Universidad de Cantabria-IDIVAL, Santander, Spain
| | - Olga Tapia
- Departamento de Anatomía y Biología Celular and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", Universidad de Cantabria-IDIVAL, Avd. Cardenal Herrera Oria s/n, 39011, Santander, Spain.
| | - Miguel Lafarga
- Departamento de Anatomía y Biología Celular and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", Universidad de Cantabria-IDIVAL, Avd. Cardenal Herrera Oria s/n, 39011, Santander, Spain.
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Effects of mild ozonisation on gene expression and nuclear domains organization in vitro. Toxicol In Vitro 2017; 44:100-110. [PMID: 28652203 DOI: 10.1016/j.tiv.2017.06.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 06/15/2017] [Accepted: 06/22/2017] [Indexed: 12/14/2022]
Abstract
In the last two decades, the use of ozone (O3) as a complementary medical approach has progressively been increasing; however, its application is still limited due to the numerous doubts about its possible toxicity, despite the low concentrations used in therapy. For an appropriate and safe clinical application of a potentially toxic agent such as O3, it is crucial to elucidate the cellular response to its administration. Molecular analyses and transmission electron microscopy were here combined to investigate in vitro the effects of O3 administration on transcriptional activity and nuclear domains organization of cultured SH-SY5Y neuronal cells; low O3 concentrations were used as those currently administered in clinical practice. Mild ozonisation did not affect cell proliferation or death, while molecular analyses showed an O3-induced modulation of some genes involved in the cell response to stress (HMOX1, ERCC4, CDKN1A) and in the transcription machinery (CTDSP1). Ultrastructural cytochemistry after experiments of bromouridine incorporation consistently demonstrated an increased transcriptional rate at both the nucleoplasmic (mRNA) and the nucleolar (rRNA) level. No ultrastructural alteration of nuclear domains was observed. Our molecular, ultrastructural and cytochemical data demonstrate that a mild toxic stimulus such as mild ozonisation stimulate cell protective pathways and nuclear transcription, without altering cell viability. This could possibly account for the positive effects observed in ozone-treated patients.
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Snigirevskaya ES, Komissarchik YY. Ultrastructural analysis of human leukemia U-937 cells after apoptosis induction: Localization of proteasomes and perichromatin fibers. Acta Histochem 2017; 119:471-480. [PMID: 28545761 DOI: 10.1016/j.acthis.2017.04.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/27/2017] [Accepted: 04/21/2017] [Indexed: 12/13/2022]
Abstract
We studied the ultrastructure of human histiocytic lymphoma U-937cells after apoptosis induction with two external agents, hypertonic shock and etoposide. Appearance of aggregates of particles of nuclear origin within the nuclei and cytoplasm of the induced cells was the first and the most prominent morphological sign of apoptosis. These aggregates were not coated by a membrane, had variable shape, density and size. Two types of particles dominated in the aggregates: perichromatin fibers (PFs) and proteasomes (PRs). PFs represent a morphological expression of transcriptional and co-transcriptional processing of pre-mRNA (Biggiogera et al., 2008), PRs are involved in hydrolysis of proteins and nucleoproteins, and participate in regulation of apoptosis (Ciechanover, 1998; Liu et al., 2007). We examined the ultrastructure and localization of PFs and PRs, and confirmed the proteasome nature of the latter by immunoelectron microscopy. We traced the formation and migration of the aggregates along the nucleus and their exit into the cytoplasm across the nuclear pores. Finally, we demonstrated degradation of the aggregates and relocating their content into exosomes at the terminal stages of apoptosis with aid of exosomes. We suggest that proteasomes function as morphologically definite and independent intracellular organelles. Alongside with proteasomes, autophagic vacuoles were revealed in apoptotic cells. Occurrence of autophagic vacuoles in apoptotic cells may suggest that both proteolytic pathways, autophagy and proteasome degradation, are coordinated with each other along the programmed cell death pathway.
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11
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Lenartowski R, Suwińska A, Lenartowska M. Calreticulin expression in relation to exchangeable Ca(2+) level that changes dynamically during anthesis, progamic phase, and double fertilization in Petunia. PLANTA 2015; 241:209-27. [PMID: 25262422 PMCID: PMC4282720 DOI: 10.1007/s00425-014-2178-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 09/15/2014] [Indexed: 05/25/2023]
Abstract
Calcium (Ca(2+)) plays essential roles in plant sexual reproduction, but the sites and the mechanism of Ca(2+) mobile storage during pollen-pistil interactions have not been fully defined. Because the Ca(2+)-buffering protein calreticulin (CRT) is able to bind and sequester Ca(2+), it can serve as a mobile intracellular store of easily releasable Ca(2+) and control its local concentration within the cytoplasm. Our previous studies showed an enhanced expression of Petunia hybrida CRT gene (PhCRT) during pistil transmitting tract maturation, pollen germination and tube outgrowth on the stigma, gamete fusion, and early embryogenesis. Here, we demonstrate that elevated expression of CRT results in the accumulation of this protein in response to anthesis, pollination, sperm cells deposition within the receptive synergid and fertilization, when the level of exchangeable Ca(2+) changes dynamically. CRT localizes mainly to the endoplasmic reticulum and Golgi compartments in the pistil transmitting tract cells, germinated pollen/tubes, and sporophytic/gametophytic cells of the ovule and corresponds with loosely bound Ca(2+). Additionally, the immunogold research shows, for the first time, highly selective CRT distribution in specific nuclear sub-domains. On the basis of our results, we discuss the possible functions of CRT with respect to the critical role of Ca(2+) homeostasis during key events of the multi-step process of generative reproduction in angiosperms.
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Affiliation(s)
- Robert Lenartowski
- Laboratory of Isotope and Instrumental Analysis, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland,
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Malatesta M, Cardani R, Pellicciari C, Meola G. RNA Transcription and Maturation in Skeletal Muscle Cells are Similarly Impaired in Myotonic Dystrophy and Sarcopenia: The Ultrastructural Evidence. Front Aging Neurosci 2014; 6:196. [PMID: 25126079 PMCID: PMC4115624 DOI: 10.3389/fnagi.2014.00196] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 07/15/2014] [Indexed: 01/23/2023] Open
Affiliation(s)
- Manuela Malatesta
- Anatomy and Histology Section, Department of Neurological and Movement Sciences, University of Verona , Verona , Italy
| | - Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS-Policlinico San Donato , Milan , Italy
| | - Carlo Pellicciari
- Laboratory of Cell Biology and Neurobiology, Department of Biology and Biotechnology, University of Pavia , Pavia , Italy
| | - Giovanni Meola
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS-Policlinico San Donato , Milan , Italy ; Department of Neurology, University of Milan , Milan , Italy
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Bogolyubov DS, Batalova FM, Kiselyov AM, Stepanova IS. Nuclear structures in Tribolium castaneum oocytes. Cell Biol Int 2013; 37:1061-79. [PMID: 23686847 DOI: 10.1002/cbin.10135] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 04/21/2013] [Indexed: 12/12/2022]
Abstract
The first ultrastructural and immunomorphological characteristics of the karyosphere (karyosome) and extrachromosomal nuclear bodies in the red flour beetle, Tribolium castaneum, are presented. The karyosphere forms early in the diplotene stage of meiotic prophase by the gathering of all oocyte chromosomes in a limited nuclear volume. Using the BrUTP assay, T. castaneum oocyte chromosomes united in the karyosphere maintain their transcriptional activity until the end of oocyte growth. Hyperphosphorylated RNA polymerase II and basal transcription factors (TFIID and TFIIH) were detected in the perichromatin region of the karyosphere. The T. castaneum karyosphere has an extrachromosomal capsule that separates chromosomes from the rest of the nucleoplasm. Certain structural proteins (F-actin, lamin B) were found in the capsule. Unexpectedly, the karyosphere capsule in T. castaneum oocytes was found to be enriched in TMG-capped snRNAs, which suggests that the capsule is not only a structural support for the karyosphere, but may be involved in biogenesis of snRNPs. We also identified the counterparts of 'universal' extrachromosomal nuclear domains, Cajal bodies (CBs) and interchromatin granule clusters (IGCs). Nuclear bodies containing IGC marker protein SC35 display some features unusual for typical IGCs. SC35 domains in T. castaneum oocytes are predominantly fibrillar complex bodies that do not contain trimethyl guanosine (TMG)-capped small nuclear (sn) RNAs. Microinjections of 2'-O-methyl (U)22 probes into the oocytes allowed revealing poly(A)+ RNAs in these nuclear domains. Several proteins related to mRNA export (heterogeneous ribonucleoprotein core protein A1, export adapters Y14 and Aly and export receptor NXF1) were also detected there. We believe that unusual SC35 nuclear domains of T. castaneum oocytes are possibly involved in mRNP but not snRNP biogenesis.
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Affiliation(s)
- Dmitry S Bogolyubov
- Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russia.
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Malatesta M, Giagnacovo M, Costanzo M, Cisterna B, Cardani R, Meola G. Muscleblind-like1 undergoes ectopic relocation in the nuclei of skeletal muscles in myotonic dystrophy and sarcopenia. Eur J Histochem 2013; 57:e15. [PMID: 23807294 PMCID: PMC3794341 DOI: 10.4081/ejh.2013.e15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 02/13/2013] [Accepted: 02/14/2013] [Indexed: 01/24/2023] Open
Abstract
Muscleblind-like 1 (MBNL1) is an alternative splicing factor involved in postnatal development of skeletal muscles and heart in humans and mice, and its deregulation is known to be pivotal in the onset and development of myotonic dystrophy (DM). In fact, in DM patients this protein is ectopically sequestered into intranuclear foci, thus compromising the regulation of the alternative splicing of several genes. However, despite the numerous biochemical and molecular studies, scarce attention has been paid to the intranuclear location of MBNL1 outside the foci, although previous data demonstrated that in DM patients various splicing and cleavage factors undergo an abnormal intranuclear distribution suggestive of impaired RNA processing. Interestingly, these nuclear alterations strongly remind those observed in sarcopenia i.e., the loss of muscle mass and function which physiologically occurs during ageing. On this basis, in the present investigation the ultrastructural localization of MBNL1 was analyzed in the myonuclei of skeletal muscles from healthy and DM patients as well as from adult and old (sarcopenic) mice, in the attempt to elucidate possible changes in its distribution and amount. Our data demonstrate that in both dystrophic and sarcopenic muscles MBNL1 undergoes intranuclear relocation, accumulating in its usual functional sites but also ectopically moving to domains which are usually devoid of this protein in healthy adults. This accumulation/delocalization could contribute to hamper the functionality of the whole splicing machinery, leading to a lower nuclear metabolic activity and, consequently, to a less efficient protein synthesis. Moreover, the similar nuclear alterations found in DM and sarcopenia may account for the similar muscle tissue features (myofibre atrophy, fibre size variability and centrally located nuclei), and, in general, for the aging-reminiscent phenotype observed in DM patients.
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Affiliation(s)
- M Malatesta
- Dipartimento di Scienze Neurologiche, Neuropsicologiche, Morfologiche e Motorie, Sezione di Anatomia e Istologia, Università di Verona, 37134 Verona, Italy.
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15
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Chun Y, Park B, Koh W, Lee S, Cheon Y, Kim R, Che L, Lee S. New centromeric component CENP-W is an RNA-associated nuclear matrix protein that interacts with nucleophosmin/B23 protein. J Biol Chem 2011; 286:42758-42769. [PMID: 22002061 DOI: 10.1074/jbc.m111.228411] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CENP-W was originally identified as a putative oncogene, cancer-upregulated gene 2 (CUG2) that was commonly up-regulated in many cancer tissues. Recently, CENP-W has also been identified as a new centromeric component that interacts with CENP-T. As a complex with CENP-T, CENP-W plays crucial roles in assembly of the functional kinetochore complex. In this study, the subnuclear localization of CENP-W was extensively analyzed using various approaches. We found that ectopically expressed CENP-W primarily accumulated in the nucleolus and remained substantially associated with the nucleolus in stable cells. The following fractionation study also showed that CENP-W is associated with RNA as well as DNA. Moreover, a considerable amount of CENP-W was found in the nuclear mesh-like structure, nuclear matrix, possibly indicating that CENP-W participates in diverse subnuclear activities. Finally, biochemical affinity binding analysis revealed that CENP-W specifically interacts with the nucleolar phosphoprotein, nucleophosmin (B23). Depletion of cellular B23 by siRNA treatment induced a dramatic decrease of CENP-W stability and severe mislocalization during prophase. Our data proposed that B23 may function in the assembly of the kinetochore complex by interacting with CENP-W during interphase.
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Affiliation(s)
- Younghwa Chun
- Department of Microbiology and Molecular Biology, Chungnam National University, 305-764, Daejeon, Republic of Korea
| | - Byoungwoo Park
- Department of Microbiology and Molecular Biology, Chungnam National University, 305-764, Daejeon, Republic of Korea
| | - Wansoo Koh
- Department of Microbiology and Molecular Biology, Chungnam National University, 305-764, Daejeon, Republic of Korea
| | - Sunhee Lee
- Department of Microbiology and Molecular Biology, Chungnam National University, 305-764, Daejeon, Republic of Korea
| | - Yeongmi Cheon
- Department of Microbiology and Molecular Biology, Chungnam National University, 305-764, Daejeon, Republic of Korea
| | - Raehyung Kim
- Department of Microbiology and Molecular Biology, Chungnam National University, 305-764, Daejeon, Republic of Korea
| | - Lihua Che
- Department of Microbiology and Molecular Biology, Chungnam National University, 305-764, Daejeon, Republic of Korea
| | - Soojin Lee
- Department of Microbiology and Molecular Biology, Chungnam National University, 305-764, Daejeon, Republic of Korea.
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16
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Malatesta M, Fattoretti P, Giagnacovo M, Pellicciari C, Zancanaro C. Physical training modulates structural and functional features of cell nuclei in type II myofibers of old mice. Rejuvenation Res 2011; 14:543-52. [PMID: 21978085 DOI: 10.1089/rej.2011.1175] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Aging is associated with a progressive loss of muscle mass, strength, and function, a condition known as sarcopenia, which represents an important risk factor for physical disability in elderly. The mechanisms leading to sarcopenia are still largely unknown, and no specific therapy is presently available to counteract its onset or progress. Many studies have stressed the importance of physical exercise as an effective approach to prevent/limit the age-related muscle mass loss. This study investigated the effects of physical training on pre-mRNA pathways in quadriceps and gastrocnemius muscles of old mice by ultrastructural cytochemistry: Structural and in situ molecular features of myonuclei and satellite cell nuclei of type II fibers were compared in exercised versus sedentary old mice, using adult individuals as control. Our results demonstrated that in myonuclei of old mice physical exercise stimulates pre-mRNA transcription, splicing, and export to the cytoplasm, likely increasing muscle protein turnover. In satellite cells, the effect of physical exercise seems to be limited to the reactivation of some factors involved in the transcriptional and splicing apparatus without increasing RNA production, probably making these quiescent cells more responsive to activating stimuli.
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Affiliation(s)
- Manuela Malatesta
- Department of Neurological, Neuropsychological, Morphological and Motor Sciences, Anatomy and Histology Section, University of Verona, Verona, Italy.
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17
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Malatesta M, Giagnacovo M, Renna LV, Cardani R, Meola G, Pellicciari C. Cultured myoblasts from patients affected by myotonic dystrophy type 2 exhibit senescence-related features: ultrastructural evidence. Eur J Histochem 2011; 55:e26. [PMID: 22073373 PMCID: PMC3203470 DOI: 10.4081/ejh.2011.e26] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 09/05/2011] [Indexed: 01/19/2023] Open
Abstract
Myotonic dystrophy type 2 (DM2) is an autosomal dominant disorder caused by the expansion of the tetranucleotidic repeat (CCTG)n in the first intron of the Zinc Finger Protein-9 gene. In DM2 tissues, the expanded mutant transcripts accumulate in nuclear focal aggregates where splicing factors are sequestered, thus affecting mRNA processing. Interestingly, the ultrastructural alterations in the splicing machinery observed in the myonuclei of DM2 skeletal muscles are reminiscent of the nuclear changes occurring in age-related muscle atrophy. Here, we investigated in vitro structural and functional features of satellite cell-derived myoblasts from biceps brachii, in the attempt to investigate cell senescence indices in DM2 patients by ultrastructural cytochemistry. We observed that in satellite cell-derived DM2 myoblasts, cell-senescence alterations such as cytoplasmic vacuolization, reduction of the proteosynthetic apparatus, accumulation of heterochromatin and impairment of the pre-mRNA maturation pathways occur earlier than in myoblasts from healthy patients. These results, together with preliminary in vitro observations on the early onset of defective structural features in DM2 myoblast derived-myotubes, suggest that the regeneration capability of DM2 satellite cells may be impaired, thus contributing to the muscular dystrophy in DM2 patients.
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Affiliation(s)
- M Malatesta
- Dipartimento di Scienze Neurologiche, Neuropsicologiche, Morfologiche e Motorie, Sezione di Anatomia e Istologia, University of Verona, Italy.
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18
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Malatesta M, Giagnacovo M, Cardani R, Meola G, Pellicciari C. RNA processing is altered in skeletal muscle nuclei of patients affected by myotonic dystrophy. Histochem Cell Biol 2011; 135:419-25. [PMID: 21387185 DOI: 10.1007/s00418-011-0797-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2011] [Indexed: 01/07/2023]
Abstract
Myotonic dystrophies (DMs) are characterised by highly variable clinical manifestations consisting of muscle weakness and atrophy, and a wide spectrum of extramuscular manifestations. In both DM1 and DM2 forms, expanded nucleotide sequences cause the accumulation of mutant transcripts in the nucleus, thus deregulating the function of some RNA-binding proteins and providing a plausible explanation for the multifactorial phenotype of DM patients. However, at the skeletal muscle level, no mechanistic explanation for the muscle wasting has so far been proposed. We therefore performed a study in situ by immunoelectron microscopy on biceps brachii biopsies from DM1, DM2 and healthy subjects, providing the first ultrastructural evidence on the distribution of some nuclear ribonucleoprotein (RNP)-containing structures and molecular factors involved in pre-mRNA transcription and maturation in dystrophic myonuclei. Our results demonstrated an accumulation of splicing and cleavage factors in myonuclei of both DM1 and DM2 patients, suggesting an impairment of post-transcriptional pre-mRNA pathways. The transcription of the expanded sequences in DM myonuclei would therefore hamper functionality of the whole splicing machinery, slowing down the intranuclear molecular trafficking; this would reduce the capability of myonuclei to respond to anabolic stimuli thus contributing to muscle wasting.
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Affiliation(s)
- Manuela Malatesta
- Dipartimento di Scienze Neurologiche, Neuropsicologiche, Morfologiche e Motorie, Sezione di Anatomia e Istologia, Università di Verona, Verona, Italy
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19
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Malatesta M, Meola G. Structural and functional alterations of the cell nucleus in skeletal muscle wasting: the evidence in situ. Eur J Histochem 2010; 54:e44. [PMID: 21263743 PMCID: PMC3167325 DOI: 10.4081/ejh.2010.e44] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 09/09/2010] [Indexed: 11/22/2022] Open
Abstract
The histochemical and ultrastructural analysis of the nuclear components involved in RNA transcription and splicing can reveal the occurrence of cellular dysfunctions eventually related to the onset of a pathological phenotype. In recent years, nuclear histochemistry at light and electron microscopy has increasingly been used to investigate the basic mechanisms of skeletal muscle diseases; the in situ study of nuclei of myofibres and satellite cells proved to be crucial for understanding the pathogenesis of skeletal muscle wasting in sarcopenia, myotonic dystrophy and laminopathies.
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Affiliation(s)
- M Malatesta
- Dipartimento di Scienze Neurologiche, Neuropsicologiche, Morfologiche e Motorie, Sezione di Anatomia e Istologia, Università di Verona, Italy.
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20
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Rouquette J, Cremer C, Cremer T, Fakan S. Functional nuclear architecture studied by microscopy: present and future. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 282:1-90. [PMID: 20630466 DOI: 10.1016/s1937-6448(10)82001-5] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this review we describe major contributions of light and electron microscopic approaches to the present understanding of functional nuclear architecture. The large gap of knowledge, which must still be bridged from the molecular level to the level of higher order structure, is emphasized by differences of currently discussed models of nuclear architecture. Molecular biological tools represent new means for the multicolor visualization of various nuclear components in living cells. New achievements offer the possibility to surpass the resolution limit of conventional light microscopy down to the nanometer scale and require improved bioinformatics tools able to handle the analysis of large amounts of data. In combination with the much higher resolution of electron microscopic methods, including ultrastructural cytochemistry, correlative microscopy of the same cells in their living and fixed state is the approach of choice to combine the advantages of different techniques. This will make possible future analyses of cell type- and species-specific differences of nuclear architecture in more detail and to put different models to critical tests.
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Affiliation(s)
- Jacques Rouquette
- Biocenter, Ludwig Maximilians University (LMU), Martinsried, Germany
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21
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Pre-mRNA processing is partially impaired in satellite cell nuclei from aged muscles. J Biomed Biotechnol 2010; 2010:410405. [PMID: 20490357 PMCID: PMC2872765 DOI: 10.1155/2010/410405] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Accepted: 02/03/2010] [Indexed: 01/25/2023] Open
Abstract
Satellite cells are responsible for the capacity of mature mammalian skeletal muscles to repair and maintain mass. During aging, skeletal muscle mass as well as the muscle strength and endurance progressively decrease, leading to a condition termed sarcopenia. The causes of sarcopenia are manifold and remain to be completely elucidated. One of them could be the remarkable decline in the efficiency of muscle regeneration; this has been associated with decreasing amounts of satellite cells, but also to alterations in their activation, proliferation, and/or differentiation. In this study, we investigated the satellite cell nuclei of biceps and quadriceps muscles from adult and old rats; morphometry and immunocytochemistry at light and electron microscopy have been combined to assess the organization of the nuclear RNP structural constituents involved in different steps of mRNA formation. We demonstrated that in satellite cells the RNA pathways undergo alterations during aging, possibly hampering their responsiveness to muscle damage.
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22
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Malatesta M, Biggiogera M, Cisterna B, Balietti M, Bertoni-Freddari C, Fattoretti P. Perichromatin fibrils accumulation in hepatocyte nuclei reveals alterations of pre-mRNA processing during aging. DNA Cell Biol 2010; 29:49-57. [PMID: 20025533 DOI: 10.1089/dna.2009.0880] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We previously described an unusual accumulation of perichromatin fibrils (PF)-the in situ form of pre-mRNA transcription and early splicing-in hepatocyte nuclei of old rats. Here we have investigated, by immunoelectron microscopy, the nature of such PF, analyzing the presence of transcription, splicing and cleavage factors, polyadenylated RNA, and the incorporation of bromouridine in adult and old rats. Our observations revealed alterations in amount and/or distribution of pre-mRNA transcription, splicing and cleavage factors, as well as of polyadenylated RNA, together with lower bromouridine incorporation in newly transcribed RNA in the hepatocyte nucleoplasm of old rats. Therefore, our data indicate both a decrease in pre-mRNA transcription and a slow down of PF processing and transport during aging.
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Affiliation(s)
- Manuela Malatesta
- 1 Department of Morphological and Biomedical Sciences, Anatomy and Histology Section, University of Verona, Verona, Italy
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23
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Perdoni F, Malatesta M, Cardani R, Giagnacovo M, Mancinelli E, Meola G, Pellicciari C. RNA/MBNL1-containing foci in myoblast nuclei from patients affected by myotonic dystrophy type 2: an immunocytochemical study. Eur J Histochem 2009; 53:e18. [PMID: 30256871 PMCID: PMC3168229 DOI: 10.4081/ejh.2009.e18] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2009] [Indexed: 01/01/2023] Open
Abstract
Myotonic dystrophy type 2 (DM2) is a dominantly inherited autosomal disease with multi-systemic clinical features and it is caused by expansion of a CCTG tetranucleotide repeat in the first intron of the zinc finger protein 9 (ZNF9) gene in 3q21.The expanded-CCUG-containing transcripts are retained in the cell nucleus and accumulate in the form of focal aggregates which specifically sequester the muscleblind-like 1 (MBNL1) protein, a RNA binding factor involved in the regulation of alternative splicing. The structural organization and composition of the foci are still incompletely known. In this study, the nuclear foci occurring in cultured myoblasts from DM2 patients were characterised at fluorescence and transmission electron microscopy by using a panel of antibodies recognizing transcription and processing factors of pre-mRNAs. MBNL1 proved to co-locate in the nuclear foci with snRNPs and hnRNPs, whereas no co-location was observed with RNA polymerase II, the non-RNP splicing factor SC35, the cleavage factor CStF and the PML protein. At electron microscopy the MBNL1-containing nuclear foci appeared as roundish domains showing a rather homogeneous structure and proved to contain snRNPs and hnRNPs. The sequestration of splicing factors involved in early phases of pre-mRNA processing supports the hypothesis of a general alteration in the maturation of several mRNAs, which could lead to the multiple pathological dysfunctions observed in dystrophic patients.
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Affiliation(s)
- F Perdoni
- Dipartimento di Biologia Animale, Laboratorio di Biologia cellulare e Neurobiologia, Università di Pavia, Italy
| | - M Malatesta
- Dipartimento di Scienze Morfologico-Biomediche, Sezione di Anatomia e Istologia, Università di Verona, Italy
| | - R Cardani
- Dipartimento di Biologia molecolare e Biotecnologie.,Centro per lo studio delle Malattie Neuromuscolari-CMN, and
| | - M Giagnacovo
- Dipartimento di Biologia molecolare e Biotecnologie
| | - E Mancinelli
- Dipartimento di Biologia molecolare e Biotecnologie
| | - G Meola
- Dipartimento di Neurologia, IRCCS Policlinico San Donato, Università degli Studi di Milano, Italy
| | - C Pellicciari
- Dipartimento di Biologia Animale, Laboratorio di Biologia cellulare e Neurobiologia, Università di Pavia, Italy
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Perdoni F, Bottone MG, Soldani C, Veneroni P, Alpini C, Pellicciari C, Scovassi AI. Distribution of centromeric proteins and PARP-1 during mitosis and apoptosis. Ann N Y Acad Sci 2009; 1171:32-7. [PMID: 19723035 DOI: 10.1111/j.1749-6632.2009.04729.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A large complex of proteins, called CENPs, are associated with centromeric DNA. Some of them exhibit a cell cycle-related expression (e.g., CENP-E and -F) and are required for the transition from interphase to mitosis, whereas constitutive proteins (e.g., CENP-A, -B, -C, -G, and -H) reside permanently at the centromere and are essential for the correct kinetochore assembly. Poly(ADP-ribose) polymerase-1 (PARP-1), which plays an active role in many basic processes, was described as a possible regulator of CENPs. By multicolor immunofluorescence we therefore analyzed the distribution of PARP-1 and its interaction with CENP-B, -E, and -F during mitosis and apoptosis.
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Affiliation(s)
- Federica Perdoni
- Department of Animal Biology, Laboratory of Cell Biology and Neurobiology, University of Pavia, Italy
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25
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Casafont I, Berciano MT, Lafarga M. Bortezomib induces the formation of nuclear poly(A) RNA granules enriched in Sam68 and PABPN1 in sensory ganglia neurons. Neurotox Res 2009; 17:167-78. [PMID: 19609631 DOI: 10.1007/s12640-009-9086-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 06/17/2009] [Accepted: 06/24/2009] [Indexed: 11/28/2022]
Abstract
The ubiquitin-dependent proteasome system (UPS) is the major pathway responsible for selective nuclear and cytoplasmic protein degradation. Bortezomib, a boronic acid dipeptide, is a reversible 20S proteasome inhibitor used as novel anticancer drug, particularly in the treatment of multiple myeloma and certain lymphomas. Bortezomib-induced peripheral neuropathy (BIPN) is a widely recognized dose-limiting neurotoxicity of this proteasome inhibitor, which causes a significant negative impact on the quality of life. The pathogenic mechanisms underlying bortezomib neurotoxicity are little known. In this study a rat was used as our animal model to investigate the bortezomib-induced nuclear changes in dorsal root ganglia (DRG) neurons. Our results indicate that this neuronal population is an important target of bortezomib neurotoxicity. Nuclear changes include accumulation of ubiquitin-protein conjugates, reduction of transcriptional activity, and nuclear retention of poly(A) RNAs in numerous spherical or ring-shaped dense granules. They also contained the RNA-binding proteins PABPN1 (poly(A) binding protein nuclear 1) and Sam68, but lacked the mRNA nuclear export factors REF and Y14. At the cytoplasmic level, most neurons exhibited chromatolysis, supporting the inhibition of mRNA translation. Our results indicate that bortezomib interferes with transcription, nuclear processing and transport, and cytoplasmic translation of mRNAs in DRG neurons. They also support that this neuronal dysfunction is an essential pathogenic mechanism in the BIPN, which is characterized by sensory impairment including sensory ataxia.
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Affiliation(s)
- Iñigo Casafont
- Department of Anatomy and Cell Biology and Centro de Investigación Biomédica en Red sobre Enferemedades Neurodegenerativas (CIBERNED), Faculty of Medicine, University of Cantabria, Avd. Cardenal Herrera Oria s/n, Santander, Spain
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26
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Casafont I, Bengoechea R, Tapia O, Berciano MT, Lafarga M. TDP-43 localizes in mRNA transcription and processing sites in mammalian neurons. J Struct Biol 2009; 167:235-41. [PMID: 19539030 DOI: 10.1016/j.jsb.2009.06.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 06/04/2009] [Accepted: 06/10/2009] [Indexed: 12/30/2022]
Abstract
TDP-43 is a RNA/DNA-binding protein structurally related to nuclear hnRNP proteins. Previous biochemical studies have shown that this nuclear protein plays a role in the regulation of gene transcription, alternative splicing and mRNA stability. Despite the ubiquitous distribution of TDP-43, the growing list of TDP-43 proteinopathies is primarily associated with neurodegenerative disorders. Particularly, TDP-43 redistributes to the cytoplasm and forms pathological inclusions in amyotrophic lateral sclerosis and several forms of sporadic and familiar frontotemporal lobar degeneration. Here, we have studied the nuclear compartmentalization of TDP-43 in normal rat neurons by using light and electron microscopy immunocytochemistry with molecular markers for nuclear compartments, a transcription assay with 5'-fluorouridine, and in situ hybridization for telomeric DNA. TDP-43 is concentrated in euchromatin domains, specifically in perichromatin fibrils, nuclear sites of transcription and cotranscriptional splicing. In these structures, TDP-43 colocalizes with 5'-fluorouridine incorporation sites into nascent pre-mRNA. TDP-43 is absent in transcriptionally silent centromeric and telomeric heterochromatin, as well as in the Cajal body, a transcription free nuclear compartment. Furthermore, a weak TDP-43 immunolabeling is found in nuclear speckles of splicing factors. The specific localization of TDP-43 in active sites of transcription and cotranscriptional splicing is consistent with biochemical data indicating a role of TDP-43 in the regulation of transcription and alternative splicing.
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Affiliation(s)
- Iñigo Casafont
- Department of Anatomy and Cell Biology and Centro de Investigación Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), University of Cantabria, 39011 Santander, Spain
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27
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Malatesta M, Perdoni F, Muller S, Zancanaro C, Pellicciari C. Nuclei of aged myofibres undergo structural and functional changes suggesting impairment in RNA processing. Eur J Histochem 2009; 53:e12. [PMID: 19683983 PMCID: PMC3167280 DOI: 10.4081/ejh.2009.e12] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2009] [Indexed: 12/25/2022] Open
Abstract
Advancing adult age is associated with a progressive decrease in skeletal muscle mass, strength and quality known as sarcopenia. The mechanisms underlying age-related skeletal muscle wasting and weakness are manifold and still remain to be fully elucidated. Despite the increasing evidence that the progress of muscle diseases leading to muscle atrophy/dystrophy may be related to defective RNA processing, no data on the morpho-functional features of skeletal muscle nuclei in sarcopenia are available at present. In this view, we have investigated, by combining morphometry and immunocytochemistry at light and electron microscopy, the fine structure of myonuclei as well as the distribution and amount of RNA processing factors in skeletal myofibres of biceps brachii and quadriceps femoris from adult and old rats. Results demonstrate that the myonuclei of aged type II fibres show an increased amount of condensed chromatin and lower amounts of phosphorylated polymerase II and DNA/RNA hybrid molecules, clearly indicating a decrease in pre-mRNA transcription rate compared to adult animals. In addition, myonuclei of aged fibres show decreased amounts of nucleoplasmic splicing factors and an accumulation of cleavage factors, polyadenilated RNA and perichromatin granules, suggesting a reduction in the processing and transport rate of premRNA. During ageing, it seems therefore that in rat myonuclei the entire production chain of mRNA, from synthesis to cytoplasmic export, is less efficient. This failure likely contributes to the reduced responsiveness of muscle cells to anabolic stimuli in the elderly.
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Affiliation(s)
- M Malatesta
- Dipartimento di Scienze Morfologico-Biomediche, Sezione di Anatomia e Istologia, University of Verona, Italy.
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Malatesta M, Perdoni F, Battistelli S, Muller S, Zancanaro C. The cell nuclei of skeletal muscle cells are transcriptionally active in hibernating edible dormice. BMC Cell Biol 2009; 10:19. [PMID: 19284674 PMCID: PMC2663540 DOI: 10.1186/1471-2121-10-19] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Accepted: 03/14/2009] [Indexed: 12/18/2022] Open
Abstract
Background Skeletal muscle is able to react in a rapid, dynamic way to metabolic and mechanical stimuli. In particular, exposure to either prolonged starvation or disuse results in muscle atrophy. At variance, in hibernating animals muscle atrophy may be scarce or absent after bouts of hibernation i.e., periods of prolonged (months) inactivity and food deprivation, and muscle function is fully preserved at arousal. In this study, myocytes from the quadriceps muscle of euthermic and hibernating edible dormice were investigated by a combination of morphological, morphometrical and immunocytochemical analyses at the light and electron microscopy level. The focus was on cell nuclei and mitochondria, which are highly sensitive markers of changing metabolic rate. Results Findings presented herein demonstrate that: 1) the general histology of the muscle, inclusive of muscle fibre shape and size, and the ratio of fast and slow fibre types are not affected by hibernation; 2) the fine structure of cytoplasmic and nuclear constituents is similar in euthermia and hibernation but for lipid droplets, which accumulate during lethargy; 3) during hibernation, mitochondria are larger in size with longer cristae, and 4) myonuclei maintain the same amount and distribution of transcripts and transcription factors as in euthermia. Conclusion In this study we demonstrate that skeletal muscle cells of the hibernating edible dormouse maintain their structural and functional integrity in full, even after months in the nest. A twofold explanation for that is envisaged: 1) the maintenance, during hibernation, of low-rate nuclear and mitochondrial activity counterbalancing myofibre wasting, 2) the intensive muscle stimulation (shivering) during periodic arousals in the nest, which would mimic physical exercise. These two factors would prevent muscle atrophy usually occurring in mammals after prolonged starvation and/or inactivity as a consequence of prevailing catabolism. Understanding the mechanisms responsible for skeletal muscle preservation in hibernators could pave the way to prevention and treatment of muscle wasting associated with pathological conditions or ageing as well as life in extreme environments, such as ocean deeps or spaceflights.
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Affiliation(s)
- Manuela Malatesta
- Dipartimento di Scienze Morfologico-Biomediche, Sezione di Anatomia e Istologia, University of Verona, Italy.
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Abstract
Recent advances have demonstrated that placing genes in a specific nuclear context plays an important role in the regulation of coordinated gene expression, thus adding an additional level of complexity to the mechanisms of gene regulation. Differentiation processes are characterized by dynamic changes in gene activation and silencing. These alterations are often accompanied by gene relocations in relation to other genomic regions or to nuclear compartments. Unraveling of mechanisms and dynamics of chromatin positioning will thus expand our knowledge about cellular differentiation.
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Affiliation(s)
- Christian Schöfer
- Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstr. 17, 1090 Vienna, Austria.
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