Noncoding Centromeric RNA Expression Impairs Chromosome Stability in Human and Murine Stem Cells

We analyzed the effect of transcribed noncoding RNA centromeric satellites on chromosome segregation in normal human and murine stem and fibrosarcoma cells. The overexpression of different centromeric alphoid DNAs in all cell lines induced a marked increase in chromosome mis-segregation in anaphase. Overexpression of centromeric mouse minor satellite also increased chromosome instability in the murine stem but not in human cells. Analysis of chromosome segregation in vivo showed disturbances in the mitotic progression, which was frequently unresolved. Live cell imaging revealed that overexpression of centromeric satellites resulted in several different chromosomal morphological errors in the cell nuclei. Our findings correlated with other reports that several centromeric noncoding RNAs are detected in different carcinoma cells and their expression resulted in segregation errors. Our study furnishes further insights into a novel source of genomic instability in human and murine cells. It has recently been shown that noncoding centromeric RNAs are present in some form of cancer, and thus, overexpression of several types of centromeric noncoding RNAs may be useful as a specific maker for neoplastic cells.

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lncRNA Chronos is an aging-induced inhibitor of muscle hypertrophy

The Journal of Cell Biology ◽

10.1083/jcb.201612100 ◽

2017 ◽

Vol 216 (11) ◽

pp. 3497-3507 ◽

Cited By ~ 25

Author(s):

Ronald L Neppl ◽

Chia-Ling Wu ◽

Kenneth Walsh

Keyword(s):

Skeletal Muscle ◽

Noncoding Rna ◽

Muscle Hypertrophy ◽

Systemic Disease ◽

Noncoding Rnas ◽

Rapid Progression ◽

Gradual Loss ◽

Epigenetic Modulation

Skeletal muscle exhibits remarkable plasticity in its ability to modulate its mass in response to the physiologic changes associated with functional use, systemic disease, and aging. Although a gradual loss of muscle mass normally occurs with advancing age, its increasingly rapid progression results in sarcopenia in a subset of individuals. The identities of muscle-enriched, long noncoding RNAs that regulate this process are unknown. Here, we identify a long noncoding RNA, named Chronos, whose expression in muscle is positively regulated with advancing age and negatively regulated during Akt1-mediated growth. Inhibition of Chronos induces myofiber hypertrophy both in vitro and in vivo, in part, through the epigenetic modulation of Bmp7 signaling.

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Noncoding RNAs in Vascular Diseases

Circulation Research ◽

10.1161/circresaha.119.315938 ◽

2020 ◽

Vol 126 (9) ◽

pp. 1127-1145 ◽

Cited By ~ 7

Author(s):

Nicolas Jaé ◽

Stefanie Dimmeler

Keyword(s):

Noncoding Rna ◽

Noncoding Rnas ◽

Vascular Diseases ◽

Long Noncoding Rnas ◽

Circular Rnas ◽

Therapeutic Targeting ◽

Rna Transcripts ◽

Sequencing Technologies ◽

Different Types

The advent of deep sequencing technologies led to the identification of a considerable amount of noncoding RNA transcripts, which are increasingly recognized for their functions in controlling cardiovascular diseases. MicroRNAs have already been studied for a decade, leading to the identification of several vasculoprotective and detrimental species, which might be considered for therapeutic targeting. Other noncoding RNAs such as circular RNAs, YRNAs, or long noncoding RNAs are currently gaining increasing attention, and first studies provide insights into their functions as mediators or antagonists of vascular diseases in vivo. The present review article will provide an overview of the different types of noncoding RNAs controlling the vasculature and focus on the developing field of long noncoding RNAs.

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CenH3-independent kinetochore assembly in Lepidoptera requires CENP-T

10.1101/836262 ◽

2019 ◽

Author(s):

N Cortes-Silva ◽

J Ulmer ◽

T Kiuchi ◽

E Hsieh ◽

G Cornilleau ◽

...

Keyword(s):

Chromosome Segregation ◽

Gene Editing ◽

Mitotic Progression ◽

Critical Function ◽

Kinetochore Assembly ◽

Histone H3 Variant ◽

Essential Function ◽

Necessary And Sufficient ◽

Assembly Pathways

AbstractAccurate chromosome segregation requires assembly of the multiprotein kinetochore complex at centromeres. In most eukaryotes, kinetochore assembly is primed by the histone H3 variant CenH3, which physically interacts with components of the inner kinetochore constitutive-centromere-associated-network (CCAN). Unexpected to its critical function, previous work identified that select eukaryotic lineages, including several insects, have lost CenH3, while having retained homologs of the CCAN. These findings imply alternative CCAN assembly pathways in these organisms that function in CenH3-independent manners. Here, we study the composition and assembly of CenH3-deficient kinetochores of Lepidoptera (butterflies and moths). We show that lepidopteran kinetochores consist of previously identified CCAN homologs as well as additional components including a divergent CENP-T homolog, which are required for accurate mitotic progression. Our study focuses on CENP-T that we find both necessary and sufficient to recruit the Mis12 outer kinetochore complex. In addition, CRISPR-mediated gene editing in Bombyx mori establishes an essential function of CENP-T in vivo. Finally, the retention of CENP-T homologs in other independently-derived CenH3-deficient insects indicates a conserved mechanism of kinetochore assembly between these lineages. Our study provides the first functional insights into CCAN-based kinetochore assembly pathways that function independently of CenH3, thus contributing to the emerging picture of an unexpected plasticity to build a kinetochore.

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Lessons Learned from In Vivo Studies of a Viral Noncoding RNA

mSphere ◽

10.1128/msphere.00026-16 ◽

2016 ◽

Vol 1 (2) ◽

Cited By ~ 3

Author(s):

Rodney P. Kincaid ◽

Christopher S. Sullivan

Keyword(s):

Noncoding Rna ◽

The augmin complex plays a critical role in spindle microtubule generation for mitotic progression and cytokinesis in human cells

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0901587106 ◽

2009 ◽

Vol 106 (17) ◽

pp. 6998-7003 ◽

Cited By ~ 138

Author(s):

Ryota Uehara ◽

Ryu-suke Nozawa ◽

Akiko Tomioka ◽

Sabine Petry ◽

Ronald D. Vale ◽

...

Keyword(s):

Chromosome Segregation ◽

Mitotic Spindle ◽

Critical Role ◽

Critical Factor ◽

Human Cells ◽

S2 Cells ◽

Mitotic Progression ◽

Spindle Microtubule ◽

Ring Complex

The mitotic spindle is constructed from microtubules (MTs) nucleated from centrosomes, chromosome proximal regions, and preexisting spindle MTs. Augmin, a recently identified protein complex, is a critical factor in spindle MT-based MT generation in Drosophila S2 cells. Previously, we identified one subunit of human augmin. Here, by using mass spectrometry, we identified the full human augmin complex of 8 subunits and show that it interacts with the γ-tubulin ring complex (γ-TuRC). Unlike augmin-depleted S2 cells, in which the defect in spindle-mediated MT generation is mostly compensated by centrosomal MTs, augmin knockdown alone in HeLa cells triggers the spindle checkpoint, reduces tension on sister kinetochores, and severely impairs metaphase progression. Human augmin knockdown also reduces the number of central spindle MTs during anaphase and causes late-stage cytokinesis failure. A link between augmin and γ-TuRC is likely critical for these functions, because a γ-TuRC mutant that attenuates interaction with augmin does not restore function in vivo. These results demonstrate that MT generation mediated by augmin and γ-TuRC is critical for chromosome segregation and cytokinesis in human cells.

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Long Noncoding RNA Lnc-SEMT Modulates IGF2 Expression by Sponging miR-125b to Promote Sheep Muscle Development and Growth

Cellular Physiology and Biochemistry ◽

10.1159/000492979 ◽

2018 ◽

Vol 49 (2) ◽

pp. 447-462 ◽

Cited By ~ 14

Author(s):

Caihong Wei ◽

Mingming Wu ◽

Chuduan Wang ◽

Ruizao Liu ◽

Huijing Zhao ◽

...

Keyword(s):

Skeletal Muscle ◽

Noncoding Rna ◽

Molecular Mechanisms ◽

Muscle Development ◽

Growth Traits ◽

Noncoding Rnas ◽

Livestock Production ◽

Myoblast Differentiation

Background/Aims: Long noncoding RNAs (lncRNAs) are RNA transcripts that are more than 200 nt long but have little protein-coding potential. Within the last few years, thousands of lncRNAs have been identified and their functions in biological processes have begun to be understood. Although many studies havebegun to examine the functions of many noncoding RNAs, very little is known about the functions of long noncoding (lncRNA) function of livestock production and molecular mechanisms of their functions are still lackingrelated to livestock production. Methods: Expression of sheep enhanced muscularityTranscript lncRNA (lnc-SEMT) and miR-125b were examined in sheep using quantitative reverse-transcription polymerase chain reaction. Expression of Myod (myogenic determination factor), Myog (myoglobin) and Insulin-like growth factor 2 (IGF2)were examined by Western Blot.Luciferase reporter assays were performedto confirm the relationship between lnc-SEMT and miR-125b. Results: Here, we identified a novel lnc-SEMT that promote sheep myoblast differentiation in vitro and enhanced sheep muscularity in vivo. Functional analyses showed that lnc-SEMT accelerates sheep myoblast differentiation in vitro. lnc-SEMT transgenic sheep exhibit a muscle hypertrophy phenotype characterized by increased body weight, and increased the number of muscle fibers indicating that lnc-SEMT play an important role in the regulation of skeletal muscle differentiation in vivo. Our results show that lnc-SEMT acts as a molecular sponge by antagonizing miR-125b to control IGF2 protein labundance in vitro and in vivo. Conclusion: In brief, lnc-SEMT is the first example of a lncRNA could be a useful candidate for improving biological growth traits such as skeletal muscle production in sheep.

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Unconventional kinetochore kinases KKT10/19 promote the metaphase to anaphase transition in Trypanosoma brucei

10.1101/806224 ◽

2019 ◽

Cited By ~ 1

Author(s):

Midori Ishii ◽

Bungo Akiyoshi

Keyword(s):

Trypanosoma Brucei ◽

Chromosome Segregation ◽

Kinase Activity ◽

Spindle Checkpoint ◽

Kinase Domain ◽

Mitotic Progression ◽

Significant Delay ◽

Terminal Part ◽

Macromolecular Protein

AbstractThe kinetochore is a macromolecular protein complex that drives chromosome segregation in eukaryotes. Unlike most eukaryotes that have canonical kinetochore proteins, evolutionarily divergent kinetoplastids such as Trypanosoma brucei have unconventional kinetochore proteins. T. brucei also lacks a canonical spindle checkpoint system and it therefore remains unknown how mitotic progression is regulated in this organism. Here we characterized two paralogous kinetochore proteins with a CLK-like kinase domain, KKT10 and KKT19, which localize at kinetochores in metaphase but disappear at the onset of anaphase. We found that these proteins are functionally redundant. Double knockdown of KKT10/19 led to a significant delay in the metaphase to anaphase transition. A kinase-dead mutant of KKT10 failed to rescue the KKT10/19 depletion phenotype, suggesting that its kinase activity is essential. We also found that phosphorylation of two kinetochore proteins KKT4 and KKT7 depends on KKT10/19 in vivo. Finally, we showed that the N-terminal part of KKT7 directly interacts with KKT10 and that kinetochore localization of KKT10 depends not only on KKT7 but also on the KKT8 complex. Our results reveal that kinetochore localization of KKT10/19 is tightly controlled to regulate the metaphase to anaphase transition in T. brucei.SummaryTrypanosoma brucei has unique kinetochore proteins and lacks a canonical spindle checkpoint system. How mitotic progression is regulated in this organism remains unclear. Here we show that two redundant protein kinases KKT10/19 promote the metaphase to anaphase transition.

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Reduced USP22 Expression Impairs Mitotic Removal of H2B Monoubiquitination, Alters Chromatin Compaction and Induces Chromosome Instability That May Promote Oncogenesis

Cancers ◽

10.3390/cancers13051043 ◽

2021 ◽

Vol 13 (5) ◽

pp. 1043

Author(s):

Lucile M. Jeusset ◽

Brent J. Guppy ◽

Zelda Lichtensztejn ◽

Darin McDonald ◽

Kirk J. McManus

Keyword(s):

Chromosome Segregation ◽

Molecular Mechanisms ◽

Chromosome Instability ◽

Critical Determinant ◽

Chromatin Compaction ◽

Cancer Pathogenesis ◽

Mitotic Chromatin ◽

Early Mitosis

Chromosome instability (CIN) is an enabling feature of oncogenesis associated with poor patient outcomes, whose genetic determinants remain largely unknown. As mitotic chromatin compaction defects can compromise the accuracy of chromosome segregation into daughter cells and drive CIN, characterizing the molecular mechanisms ensuring accurate chromatin compaction may identify novel CIN genes. In vitro, histone H2B monoubiquitination at lysine 120 (H2Bub1) impairs chromatin compaction, while in vivo H2Bub1 is rapidly depleted from chromatin upon entry into mitosis, suggesting that H2Bub1 removal may be a pre-requisite for mitotic fidelity. The deubiquitinating enzyme USP22 catalyzes H2Bub1 removal in interphase and may also be required for H2Bub1 removal in early mitosis to maintain chromosome stability. In this study, we demonstrate that siRNA-mediated USP22 depletion increases H2Bub1 levels in early mitosis and induces CIN phenotypes associated with mitotic chromatin compaction defects revealed by super-resolution microscopy. Moreover, USP22-knockout models exhibit continuously changing chromosome complements over time. These data identify mitotic removal of H2Bub1 as a critical determinant of chromatin compaction and faithful chromosome segregation. We further demonstrate that USP22 is a CIN gene, indicating that USP22 deletions, which are frequent in many tumor types, may drive genetic heterogeneity and contribute to cancer pathogenesis.

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Ultrastructural modification of cellular interactions in cancer tumor

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082455 ◽

1978 ◽

Vol 36 (2) ◽

pp. 318-319

Author(s):

N. P. Dmitrieva

Keyword(s):

Cancer Cells ◽

Human Thyroid ◽

Adjacent Cell ◽

Main Role ◽

Cellular Interactions ◽

Electron Microscopic ◽

Cancer Tumor ◽

Normal Human ◽

Characteristic Features

One of the most characteristic features of cancer cells is their ability to metastasia. It is suggested that the modifications of the structure and properties of cancer cells surfaces play the main role in this process. The present work was aimed at finding out what ultrastructural features apear in tumor in vivo which removal of individual cancer cells from the cell population can provide. For this purpose the cellular interactions in the normal human thyroid and cancer tumor of this gland electron microscopic were studied. The tissues were fixed in osmium tetroxide and were embedded in Araldite-Epon.In normal human thyroid the most common type of intercellular contacts was represented by simple junction formed by the parallelalignment of adjacent cell membranees leaving in between an intermembranes space 15-20 nm filled with electronlucid material (Fig. 1a). Sometimes in the basal part of cells dilatations of the intercellular space 40-50 nm wide were found (Fig. 1a). Here the cell surfaces may form single short microvilli.

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Meiotic CENP-C is a shepherd: bridging the space between the centromere and the kinetochore in time and space

Essays in Biochemistry ◽

10.1042/ebc20190080 ◽

2020 ◽

Vol 64 (2) ◽

pp. 251-261

Author(s):

Jessica E. Fellmeth ◽

Kim S. McKim

Keyword(s):

Chromosome Segregation ◽

New Technologies ◽

Early Prophase ◽

Unique Role ◽

Kinetochore Assembly ◽

M Phase ◽

In Vivo Analysis ◽

Meiosis I

Abstract While many of the proteins involved in the mitotic centromere and kinetochore are conserved in meiosis, they often gain a novel function due to the unique needs of homolog segregation during meiosis I (MI). CENP-C is a critical component of the centromere for kinetochore assembly in mitosis. Recent work, however, has highlighted the unique features of meiotic CENP-C. Centromere establishment and stability require CENP-C loading at the centromere for CENP-A function. Pre-meiotic loading of proteins necessary for homolog recombination as well as cohesion also rely on CENP-C, as do the main scaffolding components of the kinetochore. Much of this work relies on new technologies that enable in vivo analysis of meiosis like never before. Here, we strive to highlight the unique role of this highly conserved centromere protein that loads on to centromeres prior to M-phase onset, but continues to perform critical functions through chromosome segregation. CENP-C is not merely a structural link between the centromere and the kinetochore, but also a functional one joining the processes of early prophase homolog synapsis to late metaphase kinetochore assembly and signaling.

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