Red/green Dual Fluorescence Detection of Both the Nucleus and Nucleolus in Living Cells

2009 ◽  
Vol 17 (4) ◽  
pp. 18-21 ◽  
Author(s):  
Jack Coleman ◽  
Hilary Cox ◽  
Zaiguo Li ◽  
Praveen Pande ◽  
Dee Shen ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Dna And Rna ◽  
Nuclear Domain ◽  
Immunodeficiency Virus ◽  
Ribosomal Rna Processing ◽  
Hiv 1

The nucleolus represents a highly dynamic nuclear domain arising from an equilibrium between the level of ribosomal RNA synthesis and the efficiency of ribosomal RNA processing [1, 2]. Although the nucleolus is primarily associated with ribosome biogenesis, several lines of evidence now demonstrate that it has additional functions, such as regulation of mitosis, cell-cycle progression and proliferation, many forms of stress response, and biogenesis of multiple ribonucleoprotein particles. Ribosome biogenesis is regulated throughout interphase and ceases during mitosis (Figure 1). Thus, there is a direct relationship between cell growth and nucleolar activities. Nucleoli are well known to be dramatically modified in cancer cells. Additionally, a large number of key proteins from both DNA- and RNA-containing viruses are localized in the nucleolus, including the human immunodeficiency virus (HIV)-1 Rev and Tat proteins. Targeting of viral proteins to the nucleolus not only facilitates virus replication, but may also be required for pathogenic processes. The nucleolus can also be considered a sensor of stress due to the redistribution of the ribosomal proteins in the nucleoplasm through its disruption.

scholarly journals Repressed synthesis of ribosomal proteins generates protein-specific cell cycle and morphological phenotypes

2013 ◽  
Vol 24 (23) ◽  
pp. 3620-3633 ◽  
Author(s):  
Mamata Thapa ◽  
Ananth Bommakanti ◽  
Md. Shamsuzzaman ◽  
Brian Gregory ◽  
Leigh Samsel ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Fate ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Cell Cycle Progression ◽  
Physical Structure ◽  
Specific Cell ◽  
M Cell ◽  
Cycle Progression ◽  
M Phase

The biogenesis of ribosomes is coordinated with cell growth and proliferation. Distortion of the coordinated synthesis of ribosomal components affects not only ribosome formation, but also cell fate. However, the connection between ribosome biogenesis and cell fate is not well understood. To establish a model system for inquiries into these processes, we systematically analyzed cell cycle progression, cell morphology, and bud site selection after repression of 54 individual ribosomal protein (r-protein) genes in Saccharomyces cerevisiae. We found that repression of nine 60S r-protein genes results in arrest in the G2/M phase, whereas repression of nine other 60S and 22 40S r-protein genes causes arrest in the G1 phase. Furthermore, bud morphology changes after repression of some r-protein genes. For example, very elongated buds form after repression of seven 60S r-protein genes. These genes overlap with, but are not identical to, those causing the G2/M cell cycle phenotype. Finally, repression of most r-protein genes results in changed sites of bud formation. Strikingly, the r-proteins whose repression generates similar effects on cell cycle progression cluster in the ribosome physical structure, suggesting that different topological areas of the precursor and/or mature ribosome are mechanistically connected to separate aspects of the cell cycle.

scholarly journals Coupling Between Cell Cycle Progression and the Nuclear RNA Polymerases System

2021 ◽  
Vol 8 ◽  
Author(s):  
Irene Delgado-Román ◽  
Mari Cruz Muñoz-Centeno
Keyword(s):  
Cell Cycle ◽  
Cell Fate ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Cell Cycle Progression ◽  
Mrna Translation ◽  
Rna Polymerases ◽  
Specific Cell ◽  
Cycle Progression ◽  
Nuclear Rna

Eukaryotic life is possible due to the multitude of complex and precise phenomena that take place in the cell. Essential processes like gene transcription, mRNA translation, cell growth, and proliferation, or membrane traffic, among many others, are strictly regulated to ensure functional success. Such systems or vital processes do not work and adjusts independently of each other. It is required to ensure coordination among them which requires communication, or crosstalk, between their different elements through the establishment of complex regulatory networks. Distortion of this coordination affects, not only the specific processes involved, but also the whole cell fate. However, the connection between some systems and cell fate, is not yet very well understood and opens lots of interesting questions. In this review, we focus on the coordination between the function of the three nuclear RNA polymerases and cell cycle progression. Although we mainly focus on the model organism Saccharomyces cerevisiae, different aspects and similarities in higher eukaryotes are also addressed. We will first focus on how the different phases of the cell cycle affect the RNA polymerases activity and then how RNA polymerases status impacts on cell cycle. A good example of how RNA polymerases functions impact on cell cycle is the ribosome biogenesis process, which needs the coordinated and balanced production of mRNAs and rRNAs synthesized by the three eukaryotic RNA polymerases. Distortions of this balance generates ribosome biogenesis alterations that can impact cell cycle progression. We also pay attention to those cases where specific cell cycle defects generate in response to repressed synthesis of ribosomal proteins or RNA polymerases assembly defects.

scholarly journals Measles virus inhibits human immunodeficiency virus type 1 reverse transcription and replication by blocking cell-cycle progression of CD4+ T lymphocytes

2008 ◽  
Vol 89 (4) ◽  
pp. 984-993 ◽  
Author(s):  
Mayra García ◽  
Xiao-Fang Yu ◽  
Diane E. Griffin ◽  
William J. Moss
Keyword(s):  
Cell Cycle ◽  
T Lymphocytes ◽  
Reverse Transcription ◽  
Measles Virus ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Productive Replication

Acute measles virus (MV) infection results in a decrease in plasma human immunodeficiency virus type 1 (HIV-1) RNA levels in co-infected children. An in vitro peripheral blood mononuclear cell (PBMC) culture system was used to assess the mechanisms by which MV blocks HIV-1 replication. MV inhibited proliferation of CD4+ T lymphocytes, the target cell for HIV-1 replication. In the presence of MV, cells did not progress to G1b and S phases, steps critical for the completion of HIV-1 reverse transcription and productive replication. This block in cell-cycle progression was characterized by an increased proportion of CD4+ and HIV-1-infected cells retained in the parental generation in PBMCs co-cultured with MV and HIV-1, and decreased levels of cyclins and RNA synthesis. Early HIV-1 replication was also inhibited in the presence of MV, as measured by reduced expression of a luciferase reporter gene and lower levels of both early (LTR) and late (LTR–gag) DNA intermediates of HIV-1 reverse transcription in the presence of CCR5-tropic HIV-1. The effects of MV on lymphoproliferation and p24 antigen production were reproduced by n-butyrate and hydroxyurea, drugs that block the cell cycle in G1a and G1/S, respectively. It was concluded that MV inhibits HIV-1 productive replication in part by blocking the proliferation of CD4+ T lymphocytes.

scholarly journals Progression to the G1b Phase of the Cell Cycle Is Required for Completion of Human Immunodeficiency Virus Type 1 Reverse Transcription in T Cells

1998 ◽  
Vol 72 (4) ◽  
pp. 3161-3168 ◽  
Author(s):  
Yael D. Korin ◽  
Jerome A. Zack
Keyword(s):  
Cell Cycle ◽  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Reverse Transcription ◽  
Cell Cycle Progression ◽  
Target Cells ◽  
Cycle Progression ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Successful infection by human immunodeficiency virus type 1 (HIV-1) requires the activation of target cells. Infection of quiescent peripheral CD4 lymphocytes by HIV-1 results in incomplete, labile, reverse transcripts. In the present study, we isolated highly purified quiescent T cells and utilized the CD3/CD28 activation pathways as well as cell cycle inhibitors to further define the role of costimulation and cell cycle progression in HIV-1 reverse transcription. Activation with αCD3 alone resulted in cell cycle progression into only G1a and incomplete HIV-1 reverse transcription. Costimulation through the CD28 receptor and transition into G1b was required to efficiently complete the reverse transcription process. These findings have relevance to immune activation in vivo, since lymphocytes rendered anergic by a single activation signal would be nonpermissive for productive infection with HIV-1. Importantly, these data also suggest that HIV vector-based genetic transduction strategies might be successful only in target cells that transition into the G1b phase of the cell cycle.

scholarly journals Emerging concepts of nucleolar assembly

2002 ◽  
Vol 115 (11) ◽  
pp. 2265-2270 ◽  
Author(s):  
Danièle Hernandez-Verdun ◽  
Pascal Roussel ◽  
Jeannine Gébrane-Younès
Keyword(s):  
Cell Cycle ◽  
Ribosome Biogenesis ◽  
Cell Cycle Progression ◽  
Cell Cycle Control ◽  
Cycle Progression ◽  
Cooperative Interactions ◽  
Cellular Processes ◽  
Nuclear Domain ◽  
New Ideas

The nucleolus is a large nuclear domain and the site of ribosome biogenesis. It is also at the parting of the ways of several cellular processes, including cell cycle progression, gene silencing, and ribonucleoprotein complex formation. Consequently, a functional nucleolus is crucial for cell survival. Recent investigations of nucleolar assembly during the cell cycle and during embryogenesis have provided an integrated view of the dynamics of this process. Moreover, they have generated new ideas about cell cycle control of nucleolar assembly, the dynamics of the delivery of the RNA processing machinery, the formation of prenucleolar bodies, the role of precursor ribosomal RNAs in stabilizing the nucleolar machinery and the fact that nucleolar assembly is completed by cooperative interactions between chromosome territories. This has opened a new area of research into the dynamics of nuclear organization and the integration of nuclear functions.

scholarly journals RRP7A links primary microcephaly to dysfunction of ribosome biogenesis, resorption of primary cilia, and neurogenesis

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Farooq ◽  
Louise Lindbæk ◽  
Nicolai Krogh ◽  
Canan Doganli ◽  
Cecilie Keller ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
Rna Processing ◽  
Ribosome Biogenesis ◽  
Cell Cycle Progression ◽  
Primary Cilia ◽  
Brain Size ◽  
Cell Model ◽  
Pathophysiological Mechanism ◽  
Primary Microcephaly ◽  
Ribosomal Rna Processing

AbstractPrimary microcephaly (MCPH) is characterized by reduced brain size and intellectual disability. The exact pathophysiological mechanism underlying MCPH remains to be elucidated, but dysfunction of neuronal progenitors in the developing neocortex plays a major role. We identified a homozygous missense mutation (p.W155C) in Ribosomal RNA Processing 7 Homolog A, RRP7A, segregating with MCPH in a consanguineous family with 10 affected individuals. RRP7A is highly expressed in neural stem cells in developing human forebrain, and targeted mutation of Rrp7a leads to defects in neurogenesis and proliferation in a mouse stem cell model. RRP7A localizes to centrosomes, cilia and nucleoli, and patient-derived fibroblasts display defects in ribosomal RNA processing, primary cilia resorption, and cell cycle progression. Analysis of zebrafish embryos supported that the patient mutation in RRP7A causes reduced brain size, impaired neurogenesis and cell proliferation, and defective ribosomal RNA processing. These findings provide novel insight into human brain development and MCPH.

scholarly journals Quantitative Analysis of Human Immunodeficiency Virus Type 1-Infected CD4+ Cell Proteome: Dysregulated Cell Cycle Progression and Nuclear Transport Coincide with Robust Virus Production

2007 ◽  
Vol 81 (14) ◽  
pp. 7571-7583 ◽  
Author(s):  
Eric Y. Chan ◽  
Wei-Jun Qian ◽  
Deborah L. Diamond ◽  
Tao Liu ◽  
Marina A. Gritsenko ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cell Cycle Progression ◽  
Virus Production ◽  
Biological Pathways ◽  
Cycle Progression ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Relatively little is known at the functional genomic level about the global host response to human immunodeficiency virus type 1 (HIV-1) infection. Microarray analyses by several laboratories, including our own, have revealed that HIV-1 infection causes significant changes in host mRNA abundance and regulation of several cellular biological pathways. However, it remains unclear what consequences these changes bring about at the protein level. Here we report the expression levels of ∼3,200 proteins in the CD4+ CEMx174 cell line after infection with the LAI strain of human immunodeficiency virus type 1 (HIV-1); the proteins were assessed using liquid chromatography-mass spectrometry coupled with stable isotope labeling and the accurate mass and time tag approach. Furthermore, we found that 687 (21%) proteins changed in abundance at the peak of virus production at 36 h postinfection. Pathway analysis revealed that the differential expression of proteins was concentrated in select biological pathways, exemplified by ubiquitin-conjugating enzymes in ubiquitination, carrier proteins in nucleocytoplasmic transport, cyclin-dependent kinase in cell cycle progression, and pyruvate dehydrogenase of the citrate cycle pathways. Moreover, we observed changes in the abundance of proteins with known interactions with HIV-1 viral proteins. Our proteomic analysis captured changes in the host protein milieu at the time of robust virus production, depicting changes in cellular processes that may contribute to virus replication. Continuing analyses are expected to focus on blocking virus replication by targeting these pathways and their effector proteins.

Eukaryotic Ribosome Assembly

2019 ◽  
Vol 88 (1) ◽  
pp. 281-306 ◽  
Author(s):  
Jochen Baßler ◽  
Ed Hurt
Keyword(s):  
Ribosomal Rna ◽  
Nuclear Export ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Cryo Electron Microscopy ◽  
A Cell ◽  
Cellular Pathways ◽  
Nucleolar Rnas ◽  
Shed Light

Ribosomes, which synthesize the proteins of a cell, comprise ribosomal RNA and ribosomal proteins, which coassemble hierarchically during a process termed ribosome biogenesis. Historically, biochemical and molecular biology approaches have revealed how preribosomal particles form and mature in consecutive steps, starting in the nucleolus and terminating after nuclear export into the cytoplasm. However, only recently, due to the revolution in cryo–electron microscopy, could pseudoatomic structures of different preribosomal particles be obtained. Together with in vitro maturation assays, these findings shed light on how nascent ribosomes progress stepwise along a dynamic biogenesis pathway. Preribosomes assemble gradually, chaperoned by a myriad of assembly factors and small nucleolar RNAs, before they reach maturity and enter translation. This information will lead to a better understanding of how ribosome synthesis is linked to other cellular pathways in humans and how it can cause diseases, including cancer, if disturbed.

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