scholarly journals A large-scale in vivo RNAi screen to identify genes involved in Notch-mediated follicle cell differentiation and cell cycle switches

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Dongyu Jia ◽  
Muhammed Soylemez ◽  
Gabriel Calvin ◽  
Randy Bornmann ◽  
Jamal Bryant ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Differentiation ◽  
Large Scale ◽  
Follicle Cell ◽  
Rnai Screen

scholarly journals Interphase Cell Cycle Dynamics of a Late-Replicating, Heterochromatic Homogeneously Staining Region: Precise Choreography of Condensation/Decondensation and Nuclear Positioning

1998 ◽  
Vol 140 (5) ◽  
pp. 975-989 ◽  
Author(s):  
Gang Li ◽  
Gail Sudlow ◽  
Andrew S. Belmont
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Dna Sequences ◽  
Large Scale ◽  
S Phase ◽  
Interphase Cell ◽  
Compact Mass ◽  
Lac Operator ◽  
Cell Cycle Dynamics

Recently we described a new method for in situ localization of specific DNA sequences, based on lac operator/repressor recognition (Robinett, C.C., A. Straight, G. Li, C. Willhelm, G. Sudlow, A. Murray, and A.S. Belmont. 1996. J. Cell Biol. 135:1685–1700). We have applied this methodology to visualize the cell cycle dynamics of an ∼90 Mbp, late-replicating, heterochromatic homogeneously staining region (HSR) in CHO cells, combining immunostaining with direct in vivo observations. Between anaphase and early G1, the HSR extends approximately twofold to a linear, ∼0.3-μm-diam chromatid, and then recondenses to a compact mass adjacent to the nuclear envelope. No further changes in HSR conformation or position are seen through mid-S phase. However, HSR DNA replication is preceded by a decondensation and movement of the HSR into the nuclear interior 4–6 h into S phase. During DNA replication the HSR resolves into linear chromatids and then recondenses into a compact mass; this is followed by a third extension of the HSR during G2/ prophase. Surprisingly, compaction of the HSR is extremely high at all stages of interphase. Preliminary ultrastructural analysis of the HSR suggests at least three levels of large-scale chromatin organization above the 30-nm fiber.

scholarly journals Cell cycle-targeting microRNAs promote differentiation by enforcing cell-cycle exit

2017 ◽  
Vol 114 (40) ◽  
pp. 10660-10665 ◽  
Author(s):  
Tobias Otto ◽  
Sheyla V. Candido ◽  
Mary S. Pilarz ◽  
Ewa Sicinska ◽  
Roderick T. Bronson ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Differentiation ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Airway Disease ◽  
Quiescent State ◽  
Cell Cycle Exit ◽  
Epithelial Cell Differentiation ◽  
Chronic Airway Disease

MicroRNAs (miRNAs) have been known to affect various biological processes by repressing expression of specific genes. Here we describe an essential function of the miR-34/449 family during differentiation of epithelial cells. We found that miR-34/449 suppresses the cell-cycle machinery in vivo and promotes cell-cycle exit, thereby allowing epithelial cell differentiation. Constitutive ablation of all six members of this miRNA family causes derepression of multiple cell cycle-promoting proteins, thereby preventing epithelial cells from exiting the cell cycle and entering a quiescent state. As a result, formation of motile multicilia is strongly inhibited in several tissues such as the respiratory epithelium and the fallopian tube. Consequently, mice lacking miR-34/449 display infertility as well as severe chronic airway disease leading to postnatal death. These results demonstrate that miRNA-mediated repression of the cell cycle is required to allow epithelial cell differentiation.

scholarly journals Retargeting of macroH2A following mitosis to cytogenetic-scale heterochromatic domains

2019 ◽  
Vol 218 (6) ◽  
pp. 1810-1823 ◽  
Author(s):  
Hanae Sato ◽  
Bin Wu ◽  
Fabien Delahaye ◽  
Robert H. Singer ◽  
John M. Greally
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Cell Differentiation ◽  
Dna Replication ◽  
Gene Silencing ◽  
In Vivo Imaging ◽  
Histone Variants ◽  
G1 Phase ◽  
Potential Contributor

The heritability of chromatin states through cell division is a potential contributor to the epigenetic maintenance of cellular memory of prior states. The macroH2A histone variant has properties of a regulator of epigenetic cell memory, including roles controlling gene silencing and cell differentiation. Its mechanisms of regional genomic targeting and maintenance through cell division are unknown. Here, we combined in vivo imaging with biochemical and genomic approaches to show that human macroH2A is incorporated into chromatin in the G1 phase of the cell cycle following DNA replication. The newly incorporated macroH2A retargets the same large heterochromatic domains where macroH2A was already enriched in the previous cell cycle. It remains heterotypic, targeting individual nucleosomes that do not already contain a macroH2A molecule. The pattern observed resembles that of a new deposition of centromeric histone variants during the cell cycle, indicating mechanistic similarities for macrodomain-scale regulation of epigenetic properties of the cell.

scholarly journals DRP1-dependent mitochondrial fission initiates follicle cell differentiation during Drosophila oogenesis

2012 ◽  
Vol 197 (4) ◽  
pp. 487-497 ◽  
Author(s):  
Kasturi Mitra ◽  
Richa Rikhy ◽  
Mary Lilly ◽  
Jennifer Lippincott-Schwartz
Keyword(s):  
Cell Cycle ◽  
Cell Differentiation ◽  
Cell Layer ◽  
Mitochondrial Fission ◽  
Follicle Cell ◽  
Follicle Cells ◽  
Developmental Defects ◽  
Drosophila Oogenesis ◽  
Regulated Expression ◽  
Regulatory Link

Exit from the cell cycle is essential for cells to initiate a terminal differentiation program during development, but what controls this transition is incompletely understood. In this paper, we demonstrate a regulatory link between mitochondrial fission activity and cell cycle exit in follicle cell layer development during Drosophila melanogaster oogenesis. Posterior-localized clonal cells in the follicle cell layer of developing ovarioles with down-regulated expression of the major mitochondrial fission protein DRP1 had mitochondrial elements extensively fused instead of being dispersed. These cells did not exit the cell cycle. Instead, they excessively proliferated, failed to activate Notch for differentiation, and exhibited downstream developmental defects. Reintroduction of mitochondrial fission activity or inhibition of the mitochondrial fusion protein Marf-1 in posterior-localized DRP1-null clones reversed the block in Notch-dependent differentiation. When DRP1-driven mitochondrial fission activity was unopposed by fusion activity in Marf-1–depleted clones, premature cell differentiation of follicle cells occurred in mitotic stages. Thus, DRP1-dependent mitochondrial fission activity is a novel regulator of the onset of follicle cell differentiation during Drosophila oogenesis.

scholarly journals A Chemical Genomics Screen to Discover Genes That Modulate Neural Stem Cell Differentiation

2011 ◽  
Vol 17 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Kevin J. Kim ◽  
Jamie Wang ◽  
Xiaohong Xu ◽  
Sharon Wu ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Stem Cell ◽  
Cell Differentiation ◽  
Neural Stem Cell ◽  
Large Scale ◽  
Kinase Inhibitors ◽  
Stem Cell Differentiation ◽  
Immunofluorescence Assay ◽  
Precursor Cells ◽  
Chemical Genomics

The authors designed a chemical genomics screen with the aim of understanding genes and pathways that modulate neural stem/precursor cell differentiation. Multipotent mouse neural precursor cells isolated from cortices of embryonic day 12 (E12) embryos were subjected to spontaneous differentiation triggered by growth factor withdrawal. A quantitative whole-well immunofluorescence assay was set up to screen tool compound sets to identify small molecules with potent, dose-dependent, and reproducible effects on increasing neural stem cell differentiation toward neuronal lineage. Among the pro-neuronal compounds, kinase inhibitors were shown to exert pro-neuronal effect via a signaling pathway associated with the kinase. The global effect of hit compounds on modulating neuronal differentiation was confirmed by an in vivo mouse study and human neural stem cells culture. This study demonstrates that a phenotypic assay using cell type–specific antibody markers can be used for a large-scale compound screen to discover targets and pathways with impacts on differentiation of lineage-restricted precursor cells toward specific lineages.

scholarly journals Re-Targeting of Macroh2A Following Mitosis to Cytogenetic-Scale Heterochromatic Domains

2018 ◽  
Author(s):  
Hanae Sato ◽  
Bin Wu ◽  
Fabien Delahaye ◽  
Robert H. Singer ◽  
John M. Greally
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Cell Differentiation ◽  
Dna Replication ◽  
Gene Silencing ◽  
Histone Variants ◽  
G1 Phase ◽  
Chromatin States ◽  
Potential Contributor

SUMMARYThe heritability of chromatin states through cell division is a potential contributor to the epigenetic maintenance of cellular memory of prior states. The macroH2A histone variant has properties of a regulator of epigenetic cell memory, including roles controlling gene silencing and cell differentiation. Its mechanisms of regional genomic targeting and maintenance through cell division are unknown. Here we combined in vivo imaging with biochemical and genomic approaches to show that human macroH2A is incorporated into chromatin in the G1 phase of the cell cycle following DNA replication. The newly-incorporated macroH2A re-targets the same, large heterochromatic domains where macroH2A was already enriched in the previous cell cycle. It remains heterotypic, targeting individual nucleosomes that do not already contain a macroH2A molecule. The pattern observed resembles that of new deposition of centromeric histone variants during the cell cycle, indicating mechanistic similarities for macrodomain-scale regulation of epigenetic properties of the cell.

scholarly journals Drosophila Immunity: A Large-Scale In Vivo RNAi Screen Identifies Five Serine Proteases Required for Toll Activation

2006 ◽  
Vol 16 (8) ◽  
pp. 808-813 ◽  
Author(s):  
Zakaria Kambris ◽  
Sylvain Brun ◽  
In-Hwan Jang ◽  
Hyuck-Jin Nam ◽  
Yves Romeo ◽  
...  
Keyword(s):  
Serine Proteases ◽  
Large Scale ◽  
Rnai Screen

The THAP–zinc finger protein THAP1 regulates endothelial cell proliferation through modulation of pRB/E2F cell-cycle target genes

Blood ◽  
2006 ◽  
Vol 109 (2) ◽  
pp. 584-594 ◽  
Author(s):  
Corinne Cayrol ◽  
Chrystelle Lacroix ◽  
Catherine Mathe ◽  
Vincent Ecochard ◽  
Michele Ceribelli ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Large Scale ◽  
Cell Cycle Progression ◽  
Target Genes ◽  
Zinc Finger Protein ◽  
Endothelial Cell Proliferation ◽  
Cycle Progression ◽  
Transcriptional Target

Abstract We recently cloned a novel human nuclear factor (designated THAP1) from postcapillary venule endothelial cells (ECs) that contains a DNA-binding THAP domain, shared with zebrafish E2F6 and several Caenorhabditis elegans proteins interacting genetically with retinoblastoma gene product (pRB). Here, we show that THAP1 is a physiologic regulator of EC proliferation and cell-cycle progression, 2 essential processes for angiogenesis. Retroviral-mediated gene transfer of THAP1 into primary human ECs inhibited proliferation, and large-scale expression profiling with microarrays revealed that THAP1-mediated growth inhibition is due to coordinated repression of pRB/E2F cell-cycle target genes. Silencing of endogenous THAP1 through RNA interference similarly inhibited EC proliferation and G1/S cell-cycle progression, and resulted in down-regulation of several pRB/E2F cell-cycle target genes, including RRM1, a gene required for S-phase DNA synthesis. Chromatin immunoprecipitation assays in proliferating ECs showed that endogenous THAP1 associates in vivo with a consensus THAP1-binding site found in the RRM1 promoter, indicating that RRM1 is a direct transcriptional target of THAP1. The similar phenotypes observed after THAP1 overexpression and silencing suggest that an optimal range of THAP1 expression is essential for EC proliferation. Together, these data provide the first links in mammals among THAP proteins, cell proliferation, and pRB/E2F cell-cycle pathways.

Pattern of differentiated nerve cells in hydra is determined by precursor migration

Development ◽  
1997 ◽  
Vol 124 (2) ◽  
pp. 569-576 ◽  
Author(s):  
G. Hager ◽  
C.N. David
Keyword(s):  
Cell Cycle ◽  
Cell Differentiation ◽  
Nerve Cell ◽  
Nerve Cells ◽  
The Body ◽  
Whole Body ◽  
Continuous Growth ◽  
Body Column ◽  
Nerve Cell Differentiation

The nervous system of the fresh water polyp hydra is built up as a nerve net spread over the whole body, with higher densities in the head and the foot. In adult hydra, as a result of continuous growth, new nerve cell differentiation takes place continuously. The pattern of nerve cell differentiation and the role of nerve cell precursor migration in establishing the pattern have been observed in vivo by vitally labelling precursor cells with DiI. The results indicate that nerve cell precursors arise directly from stem cells, complete a final cell cycle and divide, giving rise to two daughter cells, which differentiate into nerve cells. A subpopulation of the nerve cell precursors are migratory for a brief interval at the onset of the terminal cell cycle, then complete the cell cycle and divide at the site of differentiation. Labelling small patches of tissue in the head, body column and peduncle/foot with DiI indicated that formation of nerve cell precursors was nearly constant at all three positions. However, at least half of the labelled precursors in the body column migrated to the head or foot before differentiating; by contrast, precursors in head and foot differentiated in situ without significant migration. This redistribution leads to a net increase of nerve cell precursors in head and foot compared to body column and thus to the higher density of nerve cells in these regions.

scholarly journals Large-scale RNAi screen identified Dhpr as a regulator of mitochondrial morphology and tissue homeostasis

2019 ◽  
Vol 5 (9) ◽  
pp. eaax0365 ◽  
Author(s):  
Jia Zhou ◽  
Lingna Xu ◽  
Xiuying Duan ◽  
Wei Liu ◽  
Xiaocui Zhao ◽  
...  
Keyword(s):  
Large Scale ◽  
Complex Analysis ◽  
Rnai Screen ◽  
Tissue Homeostasis ◽  
Mitochondrial Morphology ◽  
Gene Encoding ◽  
Chain Complexes ◽  
Transport Chain ◽  
Gradual Loss

Mitochondria are highly dynamic organelles. Through a large-scale in vivo RNA interference (RNAi) screen that covered around a quarter of the Drosophila melanogaster genes (4000 genes), we identified 578 genes whose knockdown led to aberrant shapes or distributions of mitochondria. The complex analysis revealed that knockdown of the subunits of proteasomes, spliceosomes, and the electron transport chain complexes could severely affect mitochondrial morphology. The loss of Dhpr, a gene encoding an enzyme catalyzing tetrahydrobiopterin regeneration, leads to a reduction in the numbers of tyrosine hydroxylase neurons, shorter lifespan, and gradual loss of muscle integrity and climbing ability. The affected mitochondria in Dhpr mutants are swollen and have fewer cristae, probably due to lower levels of Drp1 S-nitrosylation. Overexpression of Drp1, but not of S-nitrosylation–defective Drp1, rescued Dhpr RNAi-induced mitochondrial defects. We propose that Dhpr regulates mitochondrial morphology and tissue homeostasis by modulating S-nitrosylation of Drp1.

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