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Chen YZ, Zimyanin V, Redemann S. Loss of the mitochondrial protein SPD-3 elevates PLK-1 levels and dysregulates mitotic events. Life Sci Alliance 2023; 6:e202302011. [PMID: 37684042 PMCID: PMC10488725 DOI: 10.26508/lsa.202302011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
In metazoans, Polo-like kinase (PLK1) controls several mitotic events including nuclear envelope breakdown, centrosome maturation, spindle assembly and progression through mitosis. Here we show that a mutation in the mitochondria-localized protein SPD-3 affects mitotic events by inducing elevated levels of PLK-1 in early Caenorhabditis elegans embryos. SPD-3 mutant embryos contain abnormally positioned mitotic chromosomes, show a delay in anaphase onset and asymmetrically disassemble the nuclear lamina. We found that more PLK-1 accumulated on centrosomes, nuclear envelope, nucleoplasm, and chromatin before NEBD, suggesting that PLK-1 overexpression is responsible for some of the observed mitotic phenotypes. In agreement with this, the chromosome positioning defects of the spd-3(oj35) mutant could be rescued by reducing PLK-1 levels. Our data suggests that the mitochondrial SPD-3 protein affects chromosome positioning and nuclear envelope integrity by up-regulating the endogenous levels of PLK-1 during early embryogenesis in C. elegans This finding suggests a novel link between mitochondria and nuclear envelope dynamics and chromosome positioning by increasing the amount of a key mitotic regulator, PLK-1, providing a novel link between mitochondria and mitosis.
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Affiliation(s)
- Yu-Zen Chen
- https://ror.org/0153tk833 Center for Membrane and Cell Physiology, School of Medicine, University of Virginia, Charlottesville, VA, USA
- https://ror.org/0153tk833 Department of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Vitaly Zimyanin
- https://ror.org/0153tk833 Center for Membrane and Cell Physiology, School of Medicine, University of Virginia, Charlottesville, VA, USA
- https://ror.org/0153tk833 Department of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Stefanie Redemann
- https://ror.org/0153tk833 Center for Membrane and Cell Physiology, School of Medicine, University of Virginia, Charlottesville, VA, USA
- https://ror.org/0153tk833 Department of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, Charlottesville, VA, USA
- https://ror.org/0153tk833 Department of Cell Biology, School of Medicine, University of Virginia, Charlottesville, VA, USA
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Chen YZ, Zimyanin V, Redemann S. Mitotic events depend on regulation of PLK-1 levels by the mitochondrial protein SPD-3. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.11.523633. [PMID: 36711457 PMCID: PMC9882028 DOI: 10.1101/2023.01.11.523633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In metazoans, Polo Kinase (Plk1) controls several mitotic events including nuclear envelope breakdown, centrosome maturation and kinetochore assembly. Here we show that mitotic events regulated by Polo Like Kinase (PLK-1) in early C. elegans embryos depend on the mitochondrial-localized protein SPD-3. spd-3 mutant one-cell embryos contain abnormally positioned mitotic chromosomes and prematurely and asymmetrically disassemble the nuclear lamina. Nuclear envelope breakdown (NEBD) in C. elegans requires direct dephosphorylation of lamin by PLK-1. In spd-3 mutants PLK-1 levels are ~6X higher in comparison to control embryos and PLK-1::GFP was highly accumulated at centrosomes, the nuclear envelope, nucleoplasm, and chromosomes prior to NEBD. Partial depletion of plk-1 in spd-3 mutant embryos rescued mitotic chromosome and spindle positioning defects indicating that these phenotypes result from higher PLK-1 levels and thus activity. Our data suggests that the mitochondrial SPD-3 protein controls NEBD and chromosome positioning by regulating the endogenous levels of PLK-1 during early embryogenesis in C. elegans . This finding suggests a novel link between mitochondria and mitotic events by controlling the amount of a key mitotic regulator, PLK-1 and thus may have further implications in the context of cancers or age-related diseases and infertility as it provides a novel link between mitochondria and mitosis.
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Affiliation(s)
- Yu-Zen Chen
- Center for Membrane and Cell Physiology, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
| | - Vitaly Zimyanin
- Center for Membrane and Cell Physiology, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
| | - Stefanie Redemann
- Center for Membrane and Cell Physiology, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia, School of Medicine, Charlottesville, VA, USA
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Jin L, Zhu HY, Kang XJ, Lin LP, Zhang PY, Tan T, Yu Y, Fan Y. Melatonin protects against oxybenzone-induced deterioration of mouse oocytes during maturation. Aging (Albany NY) 2020; 13:2727-2749. [PMID: 33373318 PMCID: PMC7880374 DOI: 10.18632/aging.202323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 11/11/2020] [Indexed: 01/12/2023]
Abstract
Oxybenzone (OBZ), an ultraviolet light filter that is widely used in sunscreens and cosmetics, is an emerging contaminant found in humans and the environment. Recent studies have shown that OBZ has been detected in women's plasma, urine, and breast milk. However, the effects of OBZ exposure on oocyte meiosis have not been addressed. In this study, we investigated the detrimental effects of OBZ on oocyte maturation and the protective roles of melatonin (MT) in OBZ-exposed mouse models. Our in vitro and in vivo results showed that OBZ suppressed oocyte maturation, while MT attenuated the meiotic defects induced by OBZ. In addition, OBZ facilitated H3K4 demethylation by increasing the expression of the Kdm5 family of genes, elevating ROS levels, decreasing GSH, impairing mitochondrial quality, and disrupting spindle configuration in oocytes. However, MT treatment resulted in significant protection against OBZ-induced damage during oocyte maturation and improved oocyte quality. The mechanisms underlying the beneficial roles of MT involved reduction of oxidative stress, inhibition of apoptosis, restoration of abnormal spindle assembly and up-regulation of H3K4me3. Collectively, our results suggest that MT protects against defects induced by OBZ during mouse oocyte maturation in vitro and in vivo.
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Affiliation(s)
- Long Jin
- Department of Gynecology and Obstetrics, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, Guangdong, China
| | - Hai-Ying Zhu
- Department of Gynecology and Obstetrics, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, Guangdong, China
| | - Xiang-Jin Kang
- Department of Gynecology and Obstetrics, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, Guangdong, China
| | - Li-Ping Lin
- Department of Gynecology and Obstetrics, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, Guangdong, China
| | - Pu-Yao Zhang
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology and Key Laboratory of Assisted Reproduction, Ministry of Education, Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China
| | - Tao Tan
- Yunnan Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Scienceand Technology, Kunming 650500, Yunnan, China
| | - Yang Yu
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology and Key Laboratory of Assisted Reproduction, Ministry of Education, Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China
| | - Yong Fan
- Department of Gynecology and Obstetrics, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, Guangdong, China
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Gao LL, Xu F, Jin Z, Ying XY, Liu JW. Microtubule‑severing protein Katanin p60 ATPase‑containing subunit A‑like 1 is involved in pole‑based spindle organization during mouse oocyte meiosis. Mol Med Rep 2019; 20:3573-3582. [PMID: 31485656 DOI: 10.3892/mmr.2019.10605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 05/31/2019] [Indexed: 11/05/2022] Open
Abstract
Microtubule‑severing proteins (MTSPs) are a group of microtubule‑associated proteins essential for multiple microtubule‑related processes, including mitosis and meiosis. Katanin p60 ATPase‑containing subunit A‑like 1 (p60 katanin‑like 1) is an MTSP that maintains the density of spindle microtubules at the poles in mitotic cells; however, to date, there have been no studies about its role in female meiosis. Using in vitro‑matured (IVM) oocytes as a model, it was first revealed that p60 katanin‑like 1 was predominant in the ovaries and oocytes, indicating its essential roles in oocyte meiosis. It was also revealed that p60 katanin‑like 1 was concentrated at the spindle poles and co‑localized and interacted with γ‑tubulin, indicating that it may be involved in pole organization. Next, specific siRNA was used to deplete p60 katanin‑like 1; the spindle organization was severely disrupted and characterized by an abnormal width:length ratio, multipolarity and extra aster microtubules out of the main spindles. Finally, it was determined that p60 katanin‑like 1 knockdown retarded oocyte meiosis, reduced fertilization, and caused abnormal mitochondrial distribution. Collectively, these results indicated that p60 katanin‑like 1 is essential for oocyte meiosis by ensuring the integrity of the spindle poles.
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Affiliation(s)
- Lei-Lei Gao
- Department of Gynecology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Fei Xu
- Department of Gynecology, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, Zhejiang 310015, P.R. China
| | - Zhen Jin
- Reproductive Genetic Center, Suzhou Municipal Hospital, Suzhou Hospital of Nanjing, Nanjing, Jiangsu 215000, P.R. China
| | - Xiao-Yan Ying
- Department of Gynecology, The Second Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu 210011, P.R. China
| | - Jin-Wei Liu
- Department of Gynecology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
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Verissimo CS, Elands R, Cheng S, Saaltink DJ, ter Horst JP, Alme MN, Pont C, van de Water B, Håvik B, Fitzsimons CP, Vreugdenhil E. Silencing of doublecortin-like (DCL) results in decreased mitochondrial activity and delayed neuroblastoma tumor growth. PLoS One 2013; 8:e75752. [PMID: 24086625 PMCID: PMC3784435 DOI: 10.1371/journal.pone.0075752] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Accepted: 08/19/2013] [Indexed: 12/17/2022] Open
Abstract
Doublecortin-like (DCL) is a microtubule-binding protein crucial for neuroblastoma (NB) cell proliferation. We have investigated whether the anti-proliferative effect of DCL knockdown is linked to reduced mitochondrial activity. We found a delay in tumor development after DCL knockdown in vivo in doxycycline-inducible NB tumor xenografts. To understand the mechanisms underlying this tumor growth retardation we performed a series of in vitro experiments in NB cell lines. DCL colocalizes with mitochondria, interacts with the mitochondrial outer membrane protein OMP25/ SYNJ2BP and DCL knockdown results in decreased expression of genes involved in oxidative phosphorylation. Moreover, DCL knockdown decreases cytochrome c oxidase activity and ATP synthesis. We identified the C-terminal Serine/Proline-rich domain and the second microtubule-binding area as crucial DCL domains for the regulation of cytochrome c oxidase activity and ATP synthesis. Furthermore, DCL knockdown causes a significant reduction in the proliferation rate of NB cells under an energetic challenge induced by low glucose availability. Together with our previous studies, our results corroborate DCL as a key player in NB tumor growth in which DCL controls not only mitotic spindle formation and the stabilization of the microtubule cytoskeleton, but also regulates mitochondrial activity and energy availability, which makes DCL a promising molecular target for NB therapy.
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Affiliation(s)
- Carla S. Verissimo
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, Leiden, the Netherlands
- * E-mail: (CSV); (EV)
| | - Rachel Elands
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, Leiden, the Netherlands
| | - Sou Cheng
- Prosensa Therapeutics B.V., Leiden, the Netherlands
| | - Dirk-Jan Saaltink
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, Leiden, the Netherlands
| | - Judith P. ter Horst
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, Leiden, the Netherlands
| | - Maria N. Alme
- Department of Biomedicine, K. G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway
| | - Chantal Pont
- Division of Toxicology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, Leiden, the Netherlands
| | - Bob van de Water
- Division of Toxicology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, Leiden, the Netherlands
| | - Bjarte Håvik
- Dr. E. Martens Research Group for Biological Psychiatry, Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Carlos P. Fitzsimons
- Centre for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands
| | - Erno Vreugdenhil
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, Leiden, the Netherlands
- Department of Human Genetics, Migraine Research Group, Leiden University Medical Center, Leiden, the Netherlands
- * E-mail: (CSV); (EV)
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Labrador L, Barroso C, Lightfoot J, Müller-Reichert T, Flibotte S, Taylor J, Moerman DG, Villeneuve AM, Martinez-Perez E. Chromosome movements promoted by the mitochondrial protein SPD-3 are required for homology search during Caenorhabditis elegans meiosis. PLoS Genet 2013; 9:e1003497. [PMID: 23671424 PMCID: PMC3649994 DOI: 10.1371/journal.pgen.1003497] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 03/21/2013] [Indexed: 11/29/2022] Open
Abstract
Pairing of homologous chromosomes during early meiosis is essential to prevent the formation of aneuploid gametes. Chromosome pairing includes a step of homology search followed by the stabilization of homolog interactions by the synaptonemal complex (SC). These events coincide with dramatic changes in nuclear organization and rapid chromosome movements that depend on cytoskeletal motors and are mediated by SUN-domain proteins on the nuclear envelope, but how chromosome mobility contributes to the pairing process remains poorly understood. We show that defects in the mitochondria-localizing protein SPD-3 cause a defect in homolog pairing without impairing nuclear reorganization or SC assembly, which results in promiscuous installation of the SC between non-homologous chromosomes. Preventing SC assembly in spd-3 mutants does not improve homolog pairing, demonstrating that SPD-3 is required for homology search at the start of meiosis. Pairing center regions localize to SUN-1 aggregates at meiosis onset in spd-3 mutants; and pairing-promoting proteins, including cytoskeletal motors and polo-like kinase 2, are normally recruited to the nuclear envelope. However, quantitative analysis of SUN-1 aggregate movement in spd-3 mutants demonstrates a clear reduction in mobility, although this defect is not as severe as that seen in sun-1(jf18) mutants, which also show a stronger pairing defect, suggesting a correlation between chromosome-end mobility and the efficiency of pairing. SUN-1 aggregate movement is also impaired following inhibition of mitochondrial respiration or dynein knockdown, suggesting that mitochondrial function is required for motor-driven SUN-1 movement. The reduced chromosome-end mobility of spd-3 mutants impairs coupling of SC assembly to homology recognition and causes a delay in meiotic progression mediated by HORMA-domain protein HTP-1. Our work reveals how chromosome mobility impacts the different early meiotic events that promote homolog pairing and suggests that efficient homology search at the onset of meiosis is largely dependent on motor-driven chromosome movement. Sexually reproducing organisms carry two copies of each chromosome (homologs), which must be separated during gamete formation to prevent chromosome duplication in each generation. This chromosome halving is achieved during meiosis, a type of cell division in which the homologs recognize and pair with one another before they become intimately glued together by a structure called the synaptonemal complex (SC). Homolog pairing and SC assembly coincide with movement of chromosomes inside the nucleus, but how chromosome mobility impacts these events is not understood. We find that the mitochondrial protein SPD-3 is required to ensure normal levels of motor-driven chromosome movement and that, although pairing-promoting proteins are normally recruited at the start of meiosis in spd-3 mutants, reduced chromosome mobility impairs homolog pairing. In contrast, SC assembly is normally started, leading to the installation of SC between non-homologous chromosomes and demonstrating a failure in the coordination of pairing and SC assembly. Reduced movement also causes a controlled delay in exit from early meiotic stages characterized by chromosome clustering and active homology search. Our findings show how the different events that lead to the correct association of homologous chromosomes during early meiosis are affected by chromosome mobility.
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Affiliation(s)
- Leticia Labrador
- MRC Clinical Sciences Centre, Imperial College Faculty of Medicine, London, United Kingdom
| | - Consuelo Barroso
- MRC Clinical Sciences Centre, Imperial College Faculty of Medicine, London, United Kingdom
| | - James Lightfoot
- MRC Clinical Sciences Centre, Imperial College Faculty of Medicine, London, United Kingdom
| | | | - Stephane Flibotte
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Jon Taylor
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Donald G. Moerman
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Anne M. Villeneuve
- Departments of Developmental Biology and Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Enrique Martinez-Perez
- MRC Clinical Sciences Centre, Imperial College Faculty of Medicine, London, United Kingdom
- * E-mail:
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7
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Romero-Moya D, Bueno C, Montes R, Navarro-Montero O, Iborra FJ, López LC, Martin M, Menendez P. Cord blood-derived CD34+ hematopoietic cells with low mitochondrial mass are enriched in hematopoietic repopulating stem cell function. Haematologica 2013; 98:1022-9. [PMID: 23349299 DOI: 10.3324/haematol.2012.079244] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The homeostasis of the hematopoietic stem/progenitor cell pool relies on a fine-tuned balance between self-renewal, differentiation and proliferation. Recent studies have proposed that mitochondria regulate these processes. Although recent work has contributed to understanding the role of mitochondria during stem cell differentiation, it remains unclear whether the mitochondrial content/function affects human hematopoietic stem versus progenitor function. We found that mitochondrial mass correlates strongly with mitochondrial membrane potential in CD34(+) hematopoietic stem/progenitor cells. We, therefore, sorted cord blood CD34(+) cells on the basis of their mitochondrial mass and analyzed the in vitro homeostasis and clonogenic potential as well as the in vivo repopulating potential of CD34(+) cells with high (CD34(+) Mito(High)) versus low (CD34(+) Mito(Low)) mitochondrial mass. The CD34(+) Mito(Low) fraction contained 6-fold more CD34(+)CD38(-) primitive cells and was enriched in hematopoietic stem cell function, as demonstrated by its significantly greater hematopoietic reconstitution potential in immuno-deficient mice. In contrast, the CD34(+) Mito(High) fraction was more enriched in hematopoietic progenitor function with higher in vitro clonogenic capacity. In vitro differentiation of CD34(+) Mito(Low) cells was significantly delayed as compared to that of CD34(+) Mito(High) cells. The eventual complete differentiation of CD34(+) Mito(Low) cells, which coincided with a robust expansion of the CD34(-) differentiated progeny, was accompanied by mitochondrial adaptation, as shown by significant increases in ATP production and expression of the mitochondrial genes ND1 and COX2. In conclusion, cord blood CD34(+) cells with low levels of mitochondrial mass are enriched in hematopoietic repopulating stem cell function whereas high levels of mitochondrial mass identify hematopoietic progenitors. A mitochondrial response underlies hematopoietic stem/progenitor cell differentiation and proliferation of lineage-committed CD34(-) cells.
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Affiliation(s)
- Damia Romero-Moya
- GENyO-Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Government, Granada, Spain
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Ellefson ML, McNally FJ. CDK-1 inhibits meiotic spindle shortening and dynein-dependent spindle rotation in C. elegans. ACTA ACUST UNITED AC 2011; 193:1229-44. [PMID: 21690306 PMCID: PMC3216336 DOI: 10.1083/jcb.201104008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Before chromosome expulsion into polar bodies during female meiosis, the APC inhibits CDK-1 to allow dynein-driven spindle rotation. In animals, the female meiotic spindle is positioned at the egg cortex in a perpendicular orientation to facilitate the disposal of half of the chromosomes into a polar body. In Caenorhabditis elegans, the metaphase spindle lies parallel to the cortex, dynein is dispersed on the spindle, and the dynein activators ASPM-1 and LIN-5 are concentrated at spindle poles. Anaphase-promoting complex (APC) activation results in dynein accumulation at spindle poles and dynein-dependent rotation of one spindle pole to the cortex, resulting in perpendicular orientation. To test whether the APC initiates spindle rotation through cyclin B–CDK-1 inactivation, separase activation, or degradation of an unknown dynein inhibitor, CDK-1 was inhibited with purvalanol A in metaphase-I–arrested, APC-depleted embryos. CDK-1 inhibition resulted in the accumulation of dynein at spindle poles and dynein-dependent spindle rotation without chromosome separation. These results suggest that CDK-1 blocks rotation by inhibiting dynein association with microtubules and with LIN-5–ASPM-1 at meiotic spindle poles and that the APC promotes spindle rotation by inhibiting CDK-1.
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Affiliation(s)
- Marina L Ellefson
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
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9
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Caenorhabditis elegans cyclin B3 is required for multiple mitotic processes including alleviation of a spindle checkpoint-dependent block in anaphase chromosome segregation. PLoS Genet 2010; 6:e1001218. [PMID: 21124864 PMCID: PMC2991249 DOI: 10.1371/journal.pgen.1001218] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 10/25/2010] [Indexed: 12/22/2022] Open
Abstract
The master regulators of the cell cycle are cyclin-dependent kinases (Cdks), which influence the function of a myriad of proteins via phosphorylation. Mitotic Cdk1 is activated by A-type, as well as B1- and B2-type, cyclins. However, the role of a third, conserved cyclin B family member, cyclin B3, is less well defined. Here, we show that Caenorhabditis elegans CYB-3 has essential and distinct functions from cyclin B1 and B2 in the early embryo. CYB-3 is required for the timely execution of a number of cell cycle events including completion of the MII meiotic division of the oocyte nucleus, pronuclear migration, centrosome maturation, mitotic chromosome condensation and congression, and, most strikingly, progression through the metaphase-to-anaphase transition. Our experiments reveal that the extended metaphase delay in CYB-3–depleted embryos is dependent on an intact spindle assembly checkpoint (SAC) and results in salient defects in the architecture of holocentric metaphase chromosomes. Furthermore, genetically increasing or decreasing dynein activity results in the respective suppression or enhancement of CYB-3–dependent defects in cell cycle progression. Altogether, these data reveal that CYB-3 plays a unique, essential role in the cell cycle including promoting mitotic dynein functionality and alleviation of a SAC–dependent block in anaphase chromosome segregation. Every time a cell divides in two, the genetic material, DNA, is copied; each copied chromosome is referred to as a pair of sister chromatids. Each chromatid must be cleanly separated from its sister so that each daughter cell inherits the same DNA complement as the starting cell. The mitotic spindle is a cellular machine that physically separates the sister chromatids from one another. The chromatids are attached to the spindle at kinetochores, which are structures built at specific sites (centromeres) on each chromatid. The cell monitors the attachment of each chromatid and blocks their separation until they are all properly attached. This process is called the spindle assembly checkpoint (SAC). Here we report that loss of an evolutionarily conserved cell cycle regulator, Cyclin B3/CYB-3, results in an unusual and strikingly persistent SAC–dependent delay in sister chromatid separation. Furthermore, CYB-3 promotes the activity of a cellular motor, dynein, in this and other mitotic processes. Altogether, our results indicate that Cyclin B3 genetically interacts with mitotic dynein and is absolutely required to satisfy a SAC–dependent inhibition in sister chromatid separation.
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10
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Mantel C, Messina-Graham S, Broxmeyer HE. Upregulation of nascent mitochondrial biogenesis in mouse hematopoietic stem cells parallels upregulation of CD34 and loss of pluripotency: a potential strategy for reducing oxidative risk in stem cells. Cell Cycle 2010; 9:2008-17. [PMID: 20495374 DOI: 10.4161/cc.9.10.11733] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Oxidative damage by reactive oxygen species generated in mitochondria is a potential cause of stem-cell dysregulation. Little is known about how hematopoietic stem cells mitigate/lessen this risk in the face of upregulated mitochondrial biogenesis/function necessary for the energy needs of differentiation and progenitor expansion. Here we report that upregulation of mitochondrial mass in mouse hematopoietic stem cells is closely linked to the appearance of CD34 on their surface, a marker indicating loss of long-term repopulating ability. These mitochondria have low membrane potential initially, but become active before exiting the primitive LSK compartment. Steady-state hematopoiesis perturbed by global expression of SDF-1/CXCL12 transgene causes a shift in ratios of these mitochondrialy-distinct LSK populations. Based on known effects of SDF-1 and signaling by it's receptor, CXCR4, along with finding primitive progenitors with high mitochondrial mass but low activity, we suggest a model of asymmetric self-renewing stem cell division that could lessen stem cell exposure to oxidative damage.
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Affiliation(s)
- Charlie Mantel
- Department of Microbiology and Immunology, Indiana University School of Medicine; Indianapolis, IN, USA.
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11
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Moore A, Golden A. Hypothesis: Bifunctional mitochondrial proteins have centrosomal functions. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2009; 50:637-48. [PMID: 19565650 PMCID: PMC2804927 DOI: 10.1002/em.20508] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Mitochondria are dynamic organelles that are involved in a number of diverse processes. Most often the mitochondrion is associated with energy generation, but other important processes occur in this organelle such as fatty acid synthesis and amino acid metabolism. Although mitochondria encode less than 40 genes, all of the other approximately 1,000 genes required for their function are nuclear encoded. The protein products from these nuclear encoded genes are subsequently translocated to the mitochondria and utilized in the variety of processes within the organelle. Is it possible then that any of these nuclear encoded proteins could be translocated to other areas of the cell to participate in functions not normally attributed to the mitochondria? There is growing evidence that mitochondrial proteins not only localize to sites outside of the organelle, but also have functionality at these other locales. We suggest that a subset of nuclear encoded mitochondrial proteins are bifunctional and are involved in processes outside of the mitochondria. In this perspective, we will discuss published data demonstrating mitochondrial proteins that influence progression of the cell cycle, alter chromosome morphology, localize to centrosomes, and affect centrosome number in the cell. Overall, the mitochondrion is an interesting organelle that participates in a variety of vital functions. We suggest that these essential functions are not solely due to the ability of the mitochondria to produce high amounts of energy. Throughout this discussion we attempt to demonstrate that a cell cannot live without mitochondria and study this issue from a nonenergetic perspective.
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Affiliation(s)
- Akilah Moore
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes, Digestive, and Kidney Diseases/NIH, 8 Center Drive, Bethesda, MD 20892, USA
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Artal-Sanz M, Tavernarakis N. Prohibitin and mitochondrial biology. Trends Endocrinol Metab 2009; 20:394-401. [PMID: 19733482 DOI: 10.1016/j.tem.2009.04.004] [Citation(s) in RCA: 215] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2009] [Revised: 04/12/2009] [Accepted: 04/14/2009] [Indexed: 12/15/2022]
Abstract
Prohibitins are ubiquitous, evolutionarily conserved proteins that are mainly localized in mitochondria. The mitochondrial prohibitin complex comprises two subunits, PHB1 and PHB2. These two proteins assemble into a ring-like macromolecular structure at the inner mitochondrial membrane and are implicated in diverse cellular processes: from mitochondrial biogenesis and function to cell death and replicative senescence. In humans, prohibitins have been associated with various types of cancer. While their biochemical function remains poorly understood, studies in organisms ranging from yeast to mammals have provided significant insights into the role of the prohibitin complex in mitochondrial biogenesis and metabolism. Here we review recent studies and discuss their implications for deciphering the function of prohibitins in mitochondria.
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Affiliation(s)
- Marta Artal-Sanz
- Instituto de Biomedicina de Valencia, CSIC, 46010 Valencia, Spain
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Krüger N, Tolić-Nørrelykke IM. Association of mitochondria with spindle poles facilitates spindle alignment. Curr Biol 2008; 18:R646-R647. [PMID: 18682200 DOI: 10.1016/j.cub.2008.06.069] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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