scholarly journals Sequential Counteracting Kinases Restrict an Asymmetric Gene Expression Program to early G1

2010 ◽  
Vol 21 (16) ◽  
pp. 2809-2820 ◽  
Author(s):  
Emily Mazanka ◽  
Eric L. Weiss
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Daughter Cell ◽  
Kinase Activity ◽  
Hippo Signaling ◽  
Transcriptional Program ◽  
Cell Nuclei ◽  
Daughter Cells ◽  
Spatiotemporal Regulation ◽  
Expression Program

Gene expression is restricted to specific times in cell division and differentiation through close control of both activation and inactivation of transcription. In budding yeast, strict spatiotemporal regulation of the transcription factor Ace2 ensures that it acts only once in a cell's lifetime: at the M-to-G1 transition in newborn daughter cells. The Ndr/LATS family kinase Cbk1, functioning in a system similar to metazoan hippo signaling pathways, activates Ace2 and drives its accumulation in daughter cell nuclei, but the mechanism of this transcription factor's inactivation is unknown. We found that Ace2's nuclear localization is maintained by continuous Cbk1 activity and that inhibition of the kinase leads to immediate loss of phosphorylation and export to the cytoplasm. Once exported, Ace2 cannot re-enter nuclei for the remainder of the cell cycle. Two separate mechanisms enforce Ace2's cytoplasmic sequestration: 1) phosphorylation of CDK consensus sites in Ace2 by the G1 CDKs Pho85 and Cdc28/CDK1 and 2) an unknown mechanism mediated by Pho85 that is independent of its kinase activity. Direct phosphorylation of CDK consensus sites is not necessary for Ace2's cytoplasmic retention, indicating that these mechanisms function redundantly. Overall, these findings show how sequential opposing kinases limit a daughter cell specific transcriptional program to a brief period during the cell cycle and suggest that CDKs may function as cytoplasmic sequestration factors.

Bcl-2 protein localizes to the chromosomes of mitotic nuclei and is correlated with the cell cycle in cultured epithelial cell lines

1994 ◽  
Vol 107 (2) ◽  
pp. 363-371
Author(s):  
Q.L. Lu ◽  
A.M. Hanby ◽  
M.A. Nasser Hajibagheri ◽  
S.E. Gschmeissner ◽  
P.J. Lu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Epithelial Cell ◽  
Cell Lines ◽  
Cytoplasmic Localization ◽  
Human Epithelial Cell ◽  
Daughter Cells ◽  
Epithelial Cell Lines ◽  
Cell Immortalization

bcl-2 gene expression confers a survival advantage by preventing cells from entering apoptosis. In contrast to the previously described cytoplasmic localization of Bcl-2 in epithelial cells in vivo, in this study we have demonstrated, in a series of human epithelial cell lines, that Bcl-2 also localizes to mitotic nuclei. Both immunocytochemical and immunoelectron microscopical examinations localize this protein to nuclei and in particular to chromosomes. Nuclear Bcl-2 expression in these cell lines is correlated with the cell cycle. There is relatively strong expression during mitosis, most intense during prophase and metaphase, declining in telophase and then the protein becomes undetectable soon after separation of the two daughter cells. The expression and distribution of Bcl-2 is influenced by treatment with excessive thymidine. These results indicate that Bcl-2 may protect the cells from apoptosis occurring during mitosis and suggest a possible role for the protein in cell immortalization.

scholarly journals The ER Stress Surveillance (ERSU) pathway regulates daughter cell ER protein aggregate inheritance

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Francisco J Piña ◽  
Maho Niwa
Keyword(s):  
Cell Cycle ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Mother Cell ◽  
Daughter Cell ◽  
Protein Aggregates ◽  
Cytoplasmic Protein ◽  
Protein Aggregate ◽  
Daughter Cells ◽  
Simultaneous Visualization

Stress induced by cytoplasmic protein aggregates can have deleterious consequences for the cell, contributing to neurodegeneration and other diseases. Protein aggregates are also formed within the endoplasmic reticulum (ER), although the fate of ER protein aggregates, specifically during cell division, is not well understood. By simultaneous visualization of both the ER itself and ER protein aggregates, we found that ER protein aggregates that induce ER stress are retained in the mother cell by activation of the ER Stress Surveillance (ERSU) pathway, which prevents inheritance of stressed ER. In contrast, under conditions of normal ER inheritance, ER protein aggregates can enter the daughter cell. Thus, whereas cytoplasmic protein aggregates are retained in the mother cell to protect the functional capacity of daughter cells, the fate of ER protein aggregates is determined by whether or not they activate the ERSU pathway to impede transmission of the cortical ER during the cell cycle.

Gene Expression Profiling Reveals a Crucial Role for C/EBPbeta in Proliferation Pathways of ALK+ ALCL Cell Lines

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2818-2818
Author(s):  
Irina Bonzheim ◽  
Martin Irmler ◽  
Natasa Anastasov ◽  
Margit Klier ◽  
Johannes Beckers ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Statistical Analysis ◽  
Gene Expression Profiling ◽  
Cell Lines ◽  
Expression Profiling ◽  
Leucine Zipper ◽  
Cellular Proliferation ◽  
Kinase Activity ◽  
Large Cell

Abstract Introduction: ALK+ anaplastic large cell lymphomas (ALCL) overexpress C/EBPβ, as a consequence of NPM-ALK kinase activity. C/EBPβ is a leucine zipper transcription factor, which plays a major role in cellular differentiation, inflammation, proliferation and metabolism control. To determine the role of C/EBPβ in ALK+ ALCL transformation, and to identify its downstream targets, a highly specific C/EBPβ-shRNA was used to knockdown C/EBPβ. The consequences of C/EBPβ gene-silencing were analyzed by gene expression profiling. Materials and Methods: Four ALK+ ALCL cell lines, SUDHL-1, Kijk, Karpas 299 and SUP-M2 were transfected with lentivirus containing the C/EBPβ shRNA or the vector without shRNA in triplicates. Western Blot analysis and qRT-PCR were performed to quantify the knockdown effect. At day three after infection, RNA was extracted and used for Gene Chip expression analysis (Affymetrix). Using Anova software for statistical analysis, we identified genes, which were regulated in all four cell lines. The effect of C/EBPβ knockdown on proliferation, cell cycle, and viability was analyzed by MTT assay and FACS analysis. Results: In all four ALK+ ALCL, efficient C/EBPβ knockdown resulted in profound growth retardation (up to 84%) compared to control cells after 6 days of infection, and a clear shift from the S phase to the G1 phase in the cell cycle was observed. To identify genes regulated by C/EBPβ in all four cell lines, we performed statistical analysis applying a false discovery rate of 20%, and accepted only genes with a >1,1 and <0,9 fold ratio. We identfied 435 genes regulated after C/EBPβ knockdown (117 upregulated, 318 downregulated). Classification of the differentially expressed genes into biological categories revealed overrepresentation of genes involved in the regulation of kinase activity, cell cycle and proliferation, lymphocyte differentiation, and metabolic processes. In particular, kinases involved in the regulation of JNK activity, which have been shown previously to be involved in proliferation of ALCL, were highly affected by C/EBPβ knockdown. Genomatix Bibliosphere Pathway Analysis revealed C/EBPβ to be connected to pathways involving cell cycle (RUNX3, CCNG1, CDKN2A), apoptosis (FAS, PTPRC, BCL2A1, BIRC3) and MAPK cascades (TRIB1 and several MAP3Ks). Several of the genes identified contain known C/EBPβ binding sites. Conclusions: C/EBPβ silencing induces growth arrest in ALK+ALCL, which correlates with differential expression of genes involved in cell cycle, apoptosis and differentiation. This study reveals C/EBPβ as a master transcription regulator of NPM-ALK induced cellular proliferation, and therefore, an ideal candidate for targeted therapeutic intervention.

scholarly journals Nuclear Lamins a and B1

2000 ◽  
Vol 151 (6) ◽  
pp. 1155-1168 ◽  
Author(s):  
Robert D. Moir ◽  
Miri Yoon ◽  
Satya Khuon ◽  
Robert D. Goldman
Keyword(s):  
Green Fluorescent Protein ◽  
Nuclear Envelope ◽  
Daughter Cell ◽  
Fluorescent Protein ◽  
Lamin A ◽  
Cell Nuclei ◽  
Nuclear Lamins ◽  
Daughter Cells ◽  
Lamin B1 ◽  
Green Fluorescent

At the end of mitosis, the nuclear lamins assemble to form the nuclear lamina during nuclear envelope formation in daughter cells. We have fused A- and B-type nuclear lamins to the green fluorescent protein to study this process in living cells. The results reveal that the A- and B-type lamins exhibit different pathways of assembly. In the early stages of mitosis, both lamins are distributed throughout the cytoplasm in a diffusible (nonpolymerized) state, as demonstrated by fluorescence recovery after photobleaching (FRAP). During the anaphase-telophase transition, lamin B1 begins to become concentrated at the surface of the chromosomes. As the chromosomes reach the spindle poles, virtually all of the detectable lamin B1 has accumulated at their surfaces. Subsequently, this lamin rapidly encloses the entire perimeter of the region containing decondensing chromosomes in each daughter cell. By this time, lamin B1 has assembled into a relatively stable polymer, as indicated by FRAP analyses and insolubility in detergent/high ionic strength solutions. In contrast, the association of lamin A with the nucleus begins only after the major components of the nuclear envelope including pore complexes are assembled in daughter cells. Initially, lamin A is found in an unpolymerized state throughout the nucleoplasm of daughter cell nuclei in early G1 and only gradually becomes incorporated into the peripheral lamina during the first few hours of this stage of the cell cycle. In later stages of G1, FRAP analyses suggest that both green fluorescent protein lamins A and B1 form higher order polymers throughout interphase nuclei.

The shape of mitochondria and the number of mitochondrial nucleoids during the cell cycle of Euglena gracilis

1989 ◽  
Vol 93 (3) ◽  
pp. 565-570
Author(s):  
YASUKO HAYASHI ◽  
KATSUMI UEDA
Keyword(s):  
Cell Cycle ◽  
Fluorescence Microscopy ◽  
Cell Volume ◽  
Ethidium Bromide ◽  
Euglena Gracilis ◽  
Daughter Cell ◽  
Initial Value ◽  
Daughter Cells ◽  
Total Length ◽  
Mitochondrial Nucleoids

The shape of mitochondria and the number of mitochondrial nucleoids in Euglena cells were examined throughout the cell cycle by fluorescence microscopy. Both photoheterotrophic and heterotrophic cells contained a network of mitochondria that did not divide into fragments at any stage of the cell cycle. Mitochondrial nucleoids could be clearly detected in the mitochondria by staining with ethidium bromide and with DAPI. Half of the mitochondrial nucleoids entered each daughter cell during cytokinesis. Nucleoids in the newly produced daughter cells increased in number as the cells increased in size. The number of nucleoids reached double the initial value in cells at the stage just prior to mitosis. The total length of the mitochondrial net was proportional to the cell volume.

scholarly journals Reovirus-Induced Alterations in Gene Expression Related to Cell Cycle Regulation

2002 ◽  
Vol 76 (6) ◽  
pp. 2585-2594 ◽  
Author(s):  
George J. Poggioli ◽  
Roberta L. DeBiasi ◽  
Ryan Bickel ◽  
Robert Jotte ◽  
Aaron Spalding ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Differential Expression ◽  
Mitotic Spindle ◽  
Kinase Activity ◽  
Spindle Checkpoint ◽  
Cdc2 Kinase ◽  
Mitotic Spindle Checkpoint ◽  
Reovirus Infection ◽  
Serotype 1

ABSTRACT Mammalian reovirus infection results in perturbation of host cell cycle progression. Since reovirus infection is known to activate cellular transcription factors, we investigated alterations in cell cycle-related gene expression following HEK293 cell infection by using the Affymetrix U95A microarray. Serotype 3 reovirus infection results in differential expression of 10 genes classified as encoding proteins that function at the G1-to-S transition, 11 genes classified as encoding proteins that function at G2-to-M transition, and 4 genes classified as encoding proteins that function at the mitotic spindle checkpoint. Serotype 1 reovirus infection results in differential expression of four genes classified as encoding proteins that function at the G1-to-S transition and three genes classified as encoding proteins that function at G2-to-M transition but does not alter any genes classified as encoding proteins that function at the mitotic spindle checkpoint. We have previously shown that serotype 3, but not serotype 1, reovirus infection induces a G2-to-M transition arrest resulting from an inhibition of cdc2 kinase activity. Of the differentially expressed genes encoding proteins regulating the G2-to-M transition, chk1, wee1, and GADD45 are known to inhibit cdc2 kinase activity. A hypothetical model describing serotype 3 reovirus-induced inhibition of cdc2 kinase is presented, and reovirus-induced perturbations of the G1-to-S, G2-to-M, and mitotic spindle checkpoints are discussed.

scholarly journals Kaposi’s Sarcoma-Associated Herpesvirus LANA-Adjacent Regions with Distinct Functions in Episome Segregation or Maintenance

2019 ◽  
Vol 93 (6) ◽  
Author(s):  
Franceline Juillard ◽  
Erika De León Vázquez ◽  
Min Tan ◽  
Shijun Li ◽  
Kenneth M. Kaye
Keyword(s):  
Dna Replication ◽  
Daughter Cell ◽  
Upstream Sequence ◽  
Cell Nuclei ◽  
Mitotic Chromosomes ◽  
Repeat Elements ◽  
Viral Genomes ◽  
Daughter Cells ◽  
Internal Repeat ◽  
Carboxy Terminal

ABSTRACTKaposi’s sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) is a 1,162-amino-acid protein that mediates episome persistence of viral genomes. LANA binds the KSHV terminal-repeat (TR) sequence through its carboxy-terminal domain to mediate DNA replication. LANA simultaneously binds mitotic chromosomes and TR DNA to segregate virus genomes to daughter cell nuclei. Amino-terminal LANA attaches to chromosomes by binding histones H2A/H2B, and carboxy-terminal LANA contributes to mitotic-chromosome binding. Although amino- and carboxy-terminal LANA are essential for episome persistence, they are not sufficient, since deletion of all internal LANA sequence renders LANA highly deficient for episome maintenance. Internal LANA sequence upstream of the internal repeat elements contributes to episome segregation and persistence. Here, we investigate this region with a panel of LANA deletion mutants. Mutants retained the ability to associate with mitotic chromosomes and bind TR DNA. In contrast to prior results, deletion of most of this sequence did not reduce LANA’s ability to mediate DNA replication. Deletions of upstream sequence within the region compromised segregation of TR DNA to daughter cells, as assessed by retention of green fluorescent protein (GFP) expression from a replication-deficient TR plasmid. However, deletion of this upstream sequence did not reduce episome maintenance. In contrast, deletions that included an 80-amino-acid sequence immediately downstream resulted in highly deficient episome persistence. LANA with this downstream sequence deleted maintained the ability to replicate and segregate TR DNA, suggesting a unique role for the residues. Therefore, this work identifies adjacent LANA regions with distinct roles in episome segregation and persistence.IMPORTANCEKSHV LANA mediates episomal persistence of viral genomes. LANA binds the KSHV terminal-repeat (TR) sequence to mediate DNA replication and tethers KSHV DNA to mitotic chromosomes to segregate genomes to daughter cell nuclei. Here, we investigate LANA sequence upstream of the internal repeat elements that contributes to episome segregation and persistence. Mutants with deletions within this sequence maintained the ability to bind mitotic chromosomes or bind and replicate TR DNA. Deletion of upstream sequence within the region reduced segregation of TR DNA to daughter cells, but not episome maintenance. In contrast, mutants with deletions of 80 amino acids immediately downstream were highly deficient for episome persistence yet maintained the ability to replicate and segregate TR DNA, the two principal components of episome persistence, suggesting another role for the residues. In summary, this work identifies adjacent LANA sequence with distinct roles in episome segregation and persistence.

scholarly journals Genetically diverse uropathogenic Escherichia coli adopt a common transcriptional program in patients with UTIs

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Anna Sintsova ◽  
Arwen E Frick-Cheng ◽  
Sara Smith ◽  
Ali Pirani ◽  
Sargurunathan Subashchandrabose ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Uropathogenic Escherichia Coli ◽  
Transcriptional Program ◽  
Functional Responses ◽  
Translational Machinery ◽  
Tract Infections ◽  
Expression Program ◽  
Fast Growth Rate

Uropathogenic Escherichia coli (UPEC) is the major causative agent of uncomplicated urinary tract infections (UTIs). A common virulence genotype of UPEC strains responsible for UTIs is yet to be defined, due to the large variation of virulence factors observed in UPEC strains. We hypothesized that studying UPEC functional responses in patients might reveal universal UPEC features that enable pathogenesis. Here we identify a transcriptional program shared by genetically diverse UPEC strains isolated from 14 patients during uncomplicated UTIs. Strikingly, this in vivo gene expression program is marked by upregulation of translational machinery, providing a mechanism for the rapid growth within the host. Our analysis indicates that switching to a more specialized catabolism and scavenging lifestyle in the host allows for the increased translational output. Our study identifies a common transcriptional program underlying UTIs and illuminates the molecular underpinnings that likely facilitate the fast growth rate of UPEC in infected patients.

scholarly journals TgAP2IX-5 is a key transcriptional regulator of the asexual cell cycle division in Toxoplasma gondii

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Asma S. Khelifa ◽  
Cecilia Guillen Sanchez ◽  
Kevin M. Lesage ◽  
Ludovic Huot ◽  
Thomas Mouveaux ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Toxoplasma Gondii ◽  
Molecular Mechanisms ◽  
Developmental Pathways ◽  
Limiting Factor ◽  
Specific Cell ◽  
Master Regulator ◽  
Apicomplexan Parasites ◽  
Daughter Cells ◽  
Expression Program

AbstractApicomplexan parasites have evolved efficient and distinctive strategies for intracellular replication where the timing of emergence of the daughter cells (budding) is a decisive element. However, the molecular mechanisms that provide the proper timing of parasite budding remain unknown. Using Toxoplasma gondii as a model Apicomplexan, we identified a master regulator that controls the timing of the budding process. We show that an ApiAP2 transcription factor, TgAP2IX-5, controls cell cycle events downstream of centrosome duplication. TgAP2IX-5 binds to the promoter of hundreds of genes and controls the activation of the budding-specific cell cycle expression program. TgAP2IX-5 regulates the expression of specific transcription factors that are necessary for the completion of the budding cycle. Moreover, TgAP2IX-5 acts as a limiting factor that ensures that asexual proliferation continues by promoting the inhibition of the differentiation pathway. Therefore, TgAP2IX-5 is a master regulator that controls both cell cycle and developmental pathways.

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