scholarly journals The chromosome peripheral proteins play an active role in chromosome dynamics

2010 ◽  
Vol 1 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Sachihiro Matsunaga ◽  
Kiichi Fukui
Keyword(s):  
Active Role ◽  
Mitotic Chromosomes ◽  
Chromosomal Structure ◽  
Equal Distribution ◽  
Chromosome Dynamics ◽  
Daughter Cells ◽  
Sister Chromatids ◽  
Peripheral Proteins ◽  
And Function ◽  
Nucleolar Components

AbstractThe chromosome periphery is a chromosomal structure that covers the surface of mitotic chromosomes. The structure and function of the chromosome periphery has been poorly understood since its first description in 1882. It has, however, been proposed to be an insulator or barrier to protect chromosomes from subcellular substances and to act as a carrier of nuclear and nucleolar components to direct their equal distribution to daughter cells because most chromosome peripheral proteins (CPPs) are derived from the nucleolus or nucleus. Until now, more than 30 CPPs were identified in mammalians. Recent immunostaining analyses of CPPs have revealed that the chromosome periphery covers the centromeric region of mitotic chromosomes in addition to telomeres and regions between two sister chromatids. Knockdown analyses of CPPs using RNAi have revealed functions in chromosome dynamics, including cohesion of sister chromatids, kinetochore-microtubule attachments, spindle assembly and chromosome segregation. Because most CPPs are involved in various subcellular events in the nucleolus or nuclear at interphase, a temporal and spatial-specific knockdown method of CPPs in the chromosome periphery will be useful to understand the function of chromosome periphery in cell division.

scholarly journals Keeping sister chromatids together: cohesins in meiosis

Reproduction ◽  
2005 ◽  
Vol 130 (6) ◽  
pp. 783-790 ◽  
Author(s):  
E Revenkova ◽  
R Jessberger
Keyword(s):  
Sister Chromatid ◽  
Short Review ◽  
Interacting Proteins ◽  
Homologous Chromosomes ◽  
Chromosome Dynamics ◽  
Daughter Cells ◽  
The Core ◽  
Sister Chromatids ◽  
Chromatid Cohesion ◽  
Precise Distribution

Meiosis poses unique challenges to chromosome dynamics. Before entry into meiosis, each chromosome is duplicated and gives rise to two sister chromatids linked to each other by cohesion. Production of haploid gametes requires segregation of homologous chromosomes in the first meiotic division and of sister chromatids in the second. To ensure precise distribution of chromosomes to the daughter cells, sister chromatid cohesion (SCC) has to be dissolved in two steps. Maintenance and regulation of SCC is performed by the cohesin protein complex. This short review will primarily focus on the core cohesin proteins before venturing into adjacent territories with an emphasis on interacting proteins and complexes. It will also concentrate on mammalian meiosis and only occasionally discuss cohesion in other organisms.

Distribution and function of non-histone proteins in human chromosomes

1992 ◽  
Vol 50 (1) ◽  
pp. 556-557
Author(s):  
W.C. Earnshaw ◽  
C.A. Cooke
Keyword(s):  
Mitotic Spindle ◽  
Centromeric Heterochromatin ◽  
Mitotic Chromosomes ◽  
Histone Proteins ◽  
Sister Chromatids ◽  
Structural Specialization ◽  
And Function ◽  
Passenger Proteins

The role of non-histone proteins in the structure and movements of mitotic chromosomes remains poorly understood. We describe here experiments aimed at characterization of the distribution of two very different classes of these proteins. The first is composed of integral components of the centromere (or primary constriction). The second class consists of proteins that we have termed “chromosome passenger proteins”. These proteins are chromosomal during most of the cell cycle, but appear to be associated with the cytoskeleton during anaphase and telophase.The centromere regions of chromosomes perform three essential functions in mitosis. (1) They form the site of attachment of the chromosomes to the mitotic spindle. (2) They contain the mechanochemical motor molecules that are responsible for the movements of the chromosomes along microtubules. (3) They regulate the pairing of sister chromatids during mitosis. The first two of these mitotic functions are properties of a disk-shaped structural specialization, the kinetochore, which is located at the surface of the centromeric heterochromatin.

The influence of fixation on the morphology of mitotic chromosomes

1986 ◽  
Vol 28 (4) ◽  
pp. 536-539 ◽  
Author(s):  
Axel J. J. Dietrich
Keyword(s):  
Acetic Acid ◽  
Chemical Composition ◽  
Strong Influence ◽  
Chromosome Structure ◽  
Human Lymphocytes ◽  
Chromosome Morphology ◽  
Mitotic Chromosomes ◽  
Specific Chemical ◽  
C Banding ◽  
Sister Chromatids

It is well known that there is a strong influence of fixation, i.e., acetic methanol versus formaldehyde, on the chromosome morphology at stages of the first meiotic division. In this study the influence of both these types of fixation on the morphology of mitotic chromosomes was examined in human lymphocytes. After methanol – acetic acid (3:1) fixation, the chromosomes show the "classical" condensed shape in which it is not always possible to recognize the two sister chromatids. These chromosomes are accessible to the conventional G-, R-, and C-banding techniques. After formaldehyde fixation at a relatively high pH, the chromosomes are thinner and longer (two to six times) when compared with chromosomes following methanol – acetic acid fixation. They show a scaffold-like morphology, sometimes with a halo of thin material around it. In all cases the two sister chromatids could be recognized. This chromosome structure could be easily stained with silver, Giemsa, 4,6-diamino-2-phenyl-indole (DAPI), and fluorescein isocyanate isomere 1 (FITC). The results obtained following these stainings gave no indication to any specific chemical composition of a probable central scaffold. The scaffold-like structures were not accessible to G-, R-, or C-banding techniques. The only effect observed following these banding techniques was the disappearance of the halo of thin material around the central scaffold-like structure.Key words: chromosome structure, fixation influence, human lymphocytes.

The mitosis-regulating and protein-protein interaction activities of Astrin are controlled by Aurora-A-induced phosphorylation

2014 ◽  
Vol 307 (5) ◽  
pp. C466-C478 ◽  
Author(s):  
Shao-Chih Chiu ◽  
Jo-Mei Maureen Chen ◽  
Tong-You Wade Wei ◽  
Tai-Shan Cheng ◽  
Ya-Hui Candice Wang ◽  
...  
Keyword(s):  
Regulatory Networks ◽  
Spindle Assembly Checkpoint ◽  
Morphological Changes ◽  
Spindle Assembly ◽  
Aurora A ◽  
Protein Protein Interaction ◽  
Daughter Cells ◽  
Sister Chromatids ◽  
Complicated Process ◽  
Spindle Stability

Cells display dramatic morphological changes in mitosis, where numerous factors form regulatory networks to orchestrate the complicated process, resulting in extreme fidelity of the segregation of duplicated chromosomes into two daughter cells. Astrin regulates several aspects of mitosis, such as maintaining the cohesion of sister chromatids by inactivating Separase and stabilizing spindle, aligning and segregating chromosomes, and silencing spindle assembly checkpoint by interacting with Src kinase-associated phosphoprotein (SKAP) and cytoplasmic linker-associated protein-1α (CLASP-1α). To understand how Astrin is regulated in mitosis, we report here that Astrin acts as a mitotic phosphoprotein, and Aurora-A phosphorylates Astrin at Ser115. The phosphorylation-deficient mutant Astrin S115A abnormally activates spindle assembly checkpoint and delays mitosis progression, decreases spindle stability, and induces chromosome misalignment. Mechanistic analyses reveal that Astrin phosphorylation mimicking mutant S115D, instead of S115A, binds and induces ubiquitination and degradation of securin, which sequentially activates Separase, an enzyme required for the separation of sister chromatids. Moreover, S115A fails to bind mitosis regulators, including SKAP and CLASP-1α, which results in the mitotic defects observed in Astrin S115A-transfected cells. In conclusion, Aurora-A phosphorylates Astrin and guides the binding of Astrin to its cellular partners, which ensures proper progression of mitosis.

scholarly journals Midbody: From the Regulator of Cytokinesis to Postmitotic Signaling Organelle

Medicina ◽  
2018 ◽  
Vol 54 (4) ◽  
pp. 53 ◽  
Author(s):  
Ieva Antanavičiūtė ◽  
Paulius Gibieža ◽  
Rytis Prekeris ◽  
Vytenis Skeberdis
Keyword(s):  
Stem Cells ◽  
Cell Division ◽  
Intercellular Bridge ◽  
Large Protein ◽  
Daughter Cells ◽  
First Case ◽  
Tumorigenic Potential ◽  
The One ◽  
And Function ◽  
Protein Rich

Faithful cell division is crucial for successful proliferation, differentiation, and development of cells, tissue homeostasis, and preservation of genomic integrity. Cytokinesis is a terminal stage of cell division, leaving two genetically identical daughter cells connected by an intercellular bridge (ICB) containing the midbody (MB), a large protein-rich organelle, in the middle. Cell division may result in asymmetric or symmetric abscission of the ICB. In the first case, the ICB is severed on the one side of the MB, and the MB is inherited by the opposite daughter cell. In the second case, the MB is cut from both sides, expelled into the extracellular space, and later it can be engulfed by surrounding cells. Cells with lower autophagic activity, such as stem cells and cancer stem cells, are inclined to accumulate MBs. Inherited MBs affect cell polarity, modulate intra- and intercellular communication, enhance pluripotency of stem cells, and increase tumorigenic potential of cancer cells. In this review, we briefly summarize the latest knowledge on MB formation, inheritance, degradation, and function, and in addition, present and discuss our recent findings on the electrical and chemical communication of cells connected through the MB-containing ICB.

scholarly journals Developmental Expression and Functions of the Small Heat Shock Proteins in Drosophila

2018 ◽  
Vol 19 (11) ◽  
pp. 3441 ◽  
Author(s):  
Teresa Jagla ◽  
Magda Dubińska-Magiera ◽  
Preethi Poovathumkadavil ◽  
Małgorzata Daczewska ◽  
Krzysztof Jagla
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Large Family ◽  
Active Role ◽  
Stress Conditions ◽  
Developmental Expression ◽  
Shsp Gene ◽  
Time Specific ◽  
Shock Proteins ◽  
And Function

Heat shock proteins (Hsps) form a large family of evolutionarily conserved molecular chaperones that help balance protein folding and protect cells from various stress conditions. However, there is growing evidence that Hsps may also play an active role in developmental processes. Here, we take the example of developmental expression and function of one class of Hsps characterized by low molecular weight, the small Hsps (sHsps). We discuss recent reports and genome-wide datasets that support vital sHsps functions in the developing nervous system, reproductive system, and muscles. This tissue- and time-specific sHsp expression is developmentally regulated, so that the enhancer sequence of an sHsp gene expressed in developing muscle, in addition to stress-inducible elements, also carries binding sites for myogenic regulatory factors. One possible reason for sHsp genes to switch on during development and in non-stress conditions is to protect vital developing organs from environmental insults.

scholarly journals TARI TOPENG IRENG BANDUNGREJO, NGABLAK, MAGELANG

2018 ◽  
Vol 15 (2) ◽  
Author(s):  
Budi Setyastuti
Keyword(s):  
Local Community ◽  
Social Institutions ◽  
Active Role ◽  
Research Report ◽  
Data Presentation ◽  
Form And Function ◽  
Qualitative Approaches ◽  
Inhibiting Factors ◽  
And Function ◽  
Surrounding Village

<p>Penelitian bertujuan menggali bentuk dan fungsi sosial seni dalam adat budaya Bandungrejo. Penelitian menggunakan pendekatan kualitatif yang bersifat deskriptif. Metode pengumpulan data yang digunakan meliputi observasi, wawancara, dokumentasi dan studi pustaka. Teknik analisis data menggunakan deskriptif interpretatif. Penarikan simpulan melalui verifikasi, yang aktifitas terdiri dari reduksi data, sajian data dan laporan hasil penelitian. Hasil yang dicapai Topeng Ireng memiliki makna penting bagi kehidupan masyarakat Bandungrejo. Banyak fungsi yang berperan aktif kesenian rakyat Topeng Ireng bagi masyarakat di antaranya fungsi estetis, hiburan, perlambang, pengesahan lembaga sosial dan ritus kehidupan, pengintegrasian masyarakat, ritual, dan pendidikan. Faktor-faktor pendukung dan penghambat baik secara intern dan ekstern meliputi kondisi dan situasi masyarakat setempat dan kehadiran masyarakat desa sekitar.</p><p>Kata kunci: topeng ireng, upacara adat, fungsi, faktor pendukung dan penghambat.</p><p> </p><p><br />The research aims to explore the form and function of social arts in Bandungrejo cultural customs. The Research uses qualitative approaches that are descriptive. The method of collecting data used includes observations, interviews, documentation and literature review. The data analysis uses descriptive and interpretive. Conclusion withdrawal through verification, the activity consists of data reduction, data presentation and research report results. The results achieved by Topeng Ireng have an important meaning for the life of Bandungrejo. Many functions that play an active role in the folk art of Topeng Ireng are among others aesthetic functions, entertainment, symbolism, ratification of social institutions and rites of life, integration of society, rituals, and education. Supporting and inhibiting factors both internally and externally include the conditions and situation of the local community and the presence of the surrounding village community.</p><p>Keywords: ireng mask, traditional ceremony, function, supporting and inhibiting factors.</p>

scholarly journals The encapsulin from Thermatoga maritima is a flavoprotein with a symmetry matched ferritin-like cargo protein

2021 ◽  
Author(s):  
Benjamin J LaFrance ◽  
Caleb Cassidy-Amstutz ◽  
Robert J Nichols ◽  
Luke M Oltrogge ◽  
Eva Nogales ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Biochemical Analysis ◽  
Active Role ◽  
Structure And Function ◽  
Redox Active ◽  
Cargo Protein ◽  
Cargo Proteins ◽  
And Function ◽  
Flavin Binding ◽  
Unique Chemical

Bacterial nanocompartments, also known as encapsulins, are an emerging class of protein-based "organelles" found in bacteria and archaea. Encapsulins are virus-like icosahedral particles comprising a ~25-50 nm shell surrounding a specific cargo enzyme. Compartmentalization is thought to create a unique chemical environment to facilitate catalysis and isolate toxic intermediates. Many questions regarding nanocompartment structure-function remain unanswered, including how shell symmetry dictates cargo loading and to what extent the shell facilitates enzymatic activity. Here, we explore these questions using the model T. maritima nanocompartment known to encapsulate a redox-active ferritin-like protein. Biochemical analysis revealed the encapsulin shell to possess a flavin binding site located at the interface between capsomere subunits, suggesting the shell may play a direct and active role in the function of the encapsulated cargo. Furthermore, we used cryoEM to show that cargo proteins use a form of symmetry-matching to facilitate encapsulation and define stoichiometry. In the case of the T. maritima encapsulin, the decameric cargo protein with 5-fold symmetry preferentially binds to the pentameric-axis of the icosahedral shell. Taken together, these observations suggest the shell is not simply a passive barrier-it also plays a significant role in the structure and function of the cargo enzyme.

scholarly journals rough deal: a gene required for proper mitotic segregation in Drosophila.

1989 ◽  
Vol 109 (6) ◽  
pp. 2951-2961 ◽  
Author(s):  
R E Karess ◽  
D M Glover
Keyword(s):  
Cell Death ◽  
Genetic Locus ◽  
Motile Sperm ◽  
High Frequencies ◽  
Morphological Process ◽  
Daughter Cells ◽  
Chromosome Transmission ◽  
Sister Chromatids ◽  
Mitotic Abnormalities ◽  
Homozygous Mutant

We describe a genetic locus rough deal (rod) in Drosophila melanogaster, identified by mutations that interfere with the faithful transmission of chromosomes to daughter cells during mitosis. Five mutant alleles were isolated, each associated with a similar set of mitotic abnormalities in the dividing neuroblasts of homozygous mutant larvae: high frequencies of aneuploid cells and abnormal anaphase figures, in which chromatids may lag, form bridges, or completely fail to separate. Surviving homozygous adults are sterile, and show cuticular defects associated with cell death, i.e., roughened eyes, sparse abdominal bristles, and notched wing margins. The morphological process of spermatogenesis is largely unaffected and motile sperm are produced, but meiocyte aneuploidy is common. The nature of the observed abnormalities in mitotic cells suggests that the reduced fidelity of chromosome transmission to the daughter cells is due to a failure in a mechanism involved in assuring the proper release of sister chromatids.

scholarly journals Effect of triiodothyronine augmentation on rat lung surfactant phospholipids during sepsis

1997 ◽  
Vol 82 (6) ◽  
pp. 2020-2027 ◽  
Author(s):  
Sergey M. Ksenzenko ◽  
Scott B. Davidson ◽  
Amer A. Saba ◽  
Alexander P. Franko ◽  
Aml M. Raafat ◽  
...  
Keyword(s):  
Lung Surfactant ◽  
Cecal Ligation ◽  
Active Role ◽  
Lung Compliance ◽  
Rat Lung ◽  
Sprague Dawley ◽  
Surfactant Phospholipids ◽  
Surfactant Composition ◽  
And Function

Ksenzenko, Sergey M., Scott B. Davidson, Amer A. Saba, Alexander P. Franko, Aml M. Raafat, Lawrence N. Diebel, and Scott A. Dulchavsky. Effect of triiodothyronine augmentation on rat lung surfactant phospholipids during sepsis. J. Appl. Physiol. 82(6): 2020–2027, 1997.—Surfactant functional effectiveness is dependent on phospholipid compositional integrity; sepsis decreases this through an undefined mechanism. Sepsis-induced hypothyroidism is commensurate and may be related. This study examines the effect of 3,3′,5-triiodo-l-thyronine (T3) supplementation on surfactant composition and function during sepsis. Male Sprague-Dawley rats underwent sham laparotomy (Sham) or cecal ligation and puncture (CLP) with or without T3supplementation [CLP/T3 (3 ng/h)]. After 6, 12, or 24 h, surfactant was obtained by lavage. Function was assessed by a pulsating bubble surfactometer and in vivo compliance studies. Sepsis produced a decrease in surfactant phosphatidylglycerol and phosphatidic acid, with an increase in lesser surface-active lipids phosphatidylserine and phosphatidylinositol. Phosphatidylcholine content was not significantly changed. Sepsis caused an alteration in the fatty acid composition and an increase in saturation in most phospholipids. Hormonal replacement attenuated these changes. Lung compliance and surfactant adsorption were reduced by sepsis and maintained by T3treatment. Thyroid hormone may have an active role in lung functional preservation through maintenance of surfactant homeostasis during sepsis.

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