Ecdysteroid Effects on the Cell Cycle of Drosophila melanogaster Cells

1983 ◽  
pp. 93-99
Author(s):  
John D. O’Connor ◽  
Bryn Stevens
Keyword(s):  
Cell Cycle ◽  
Drosophila Melanogaster

scholarly journals The composition and organization of Drosophila heterochromatin are heterogeneous and dynamic

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Joel M Swenson ◽  
Serafin U Colmenares ◽  
Amy R Strom ◽  
Sylvain V Costes ◽  
Gary H Karpen
Keyword(s):  
Cell Cycle ◽  
Image Analysis ◽  
Drosophila Melanogaster ◽  
Gene Silencing ◽  
Epigenetic Factors ◽  
Heterochromatin Protein ◽  
Genome Wide ◽  
A Genome ◽  
Drosophila Heterochromatin ◽  
Heterochromatin Domain

Heterochromatin is enriched for specific epigenetic factors including Heterochromatin Protein 1a (HP1a), and is essential for many organismal functions. To elucidate heterochromatin organization and regulation, we purified Drosophila melanogaster HP1a interactors, and performed a genome-wide RNAi screen to identify genes that impact HP1a levels or localization. The majority of the over four hundred putative HP1a interactors and regulators identified were previously unknown. We found that 13 of 16 tested candidates (83%) are required for gene silencing, providing a substantial increase in the number of identified components that impact heterochromatin properties. Surprisingly, image analysis revealed that although some HP1a interactors and regulators are broadly distributed within the heterochromatin domain, most localize to discrete subdomains that display dynamic localization patterns during the cell cycle. We conclude that heterochromatin composition and architecture is more spatially complex and dynamic than previously suggested, and propose that a network of subdomains regulates diverse heterochromatin functions.

Cell cycle progression and cell division are sensitive to hypoxia in Drosophila melanogaster embryos

2001 ◽  
Vol 280 (5) ◽  
pp. R1555-R1563 ◽  
Author(s):  
Robert M. Douglas ◽  
Tian Xu ◽  
Gabriel G. Haddad
Keyword(s):  
Cell Cycle ◽  
Drosophila Melanogaster ◽  
Mammalian Cells ◽  
Fluorescent Protein ◽  
Immunoblot Analysis ◽  
Embryonic Cell ◽  
Cell Cycle Checkpoints ◽  
Cycle Phase ◽  
Embryonic Cells

We and others recently demonstrated that Drosophila melanogaster embryos arrest development and embryonic cells cease dividing when they are deprived of O2. To further characterize the behavior of these embryos in response to O2 deprivation and to define the O2-sensitive checkpoints in the cell cycle, embryos undergoing nuclear cycles 3–13 were subjected to O2deprivation and examined by confocal microscopy under control, hypoxic, and reoxygenation conditions. In vivo, real-time analysis of embryos carrying green fluorescent protein-kinesin demonstrated that cells arrest at two major points of the cell cycle, either at the interphase (before DNA duplication) or at metaphase, depending on the cell cycle phase at which O2 deprivation was induced. Immunoblot analysis of embryos whose cell divisions are synchronized by inducible String (cdc25 homolog) demonstrated that cyclin B was degraded during low O2 conditions in interphase-arrested embryos but not in those arrested in metaphase. Embryos resumed cell cycle activity within ∼20 min of reoxygenation, with very little apparent change in cell cycle kinetics. We conclude that there are specific points during the embryonic cell cycle that are sensitive to the O2 level in D. melanogaster. Given the fact that O2deprivation also influences the growth and development of other species, we suggest that similar hypoxia-sensitive cell cycle checkpoints may also exist in mammalian cells.

scholarly journals Cell Cycle Kinase Polo Is Controlled by a Widespread 3′ Untranslated Region Regulatory Sequence inDrosophila melanogaster

2019 ◽  
Vol 39 (15) ◽  
Author(s):  
Marta S. Oliveira ◽  
Jaime Freitas ◽  
Pedro A. B. Pinto ◽  
Ana de Jesus ◽  
Joana Tavares ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Drosophila Melanogaster ◽  
Untranslated Region ◽  
Molecular Mechanisms ◽  
Alternative Polyadenylation ◽  
Upstream Sequence ◽  
Sequence Element ◽  
Content Type ◽  
Cell Cycle Kinase

ABSTRACTAlternative polyadenylation generates transcriptomic diversity, although the physiological impact and regulatory mechanisms involved are still poorly understood. The cell cycle kinase Polo is controlled by alternative polyadenylation in the 3′ untranslated region (3′UTR), with critical physiological consequences. Here, we characterized the molecular mechanisms required forpoloalternative polyadenylation. We identified a conserved upstream sequence element (USE) close to thepoloproximal poly(A) signal. Transgenic flies without this sequence show incorrect selection ofpolopoly(A) signals with consequent downregulation of Polo expression levels and insufficient/defective activation of Polo kinetochore targets Mps1 and Aurora B. Deletion of the USE results in abnormal mitoses in neuroblasts, revealing a role for this sequencein vivo. We found that Hephaestus binds to the USE RNA and thathephaestusmutants display defects inpoloalternative polyadenylation concomitant with a striking reduction in Polo protein levels, leading to mitotic errors and aneuploidy. Bioinformatic analyses show that the USE is preferentially localized upstream of noncanonical polyadenylation signals inDrosophila melanogastergenes. Taken together, our results revealed the molecular mechanisms involved inpoloalternative polyadenylation, with remarkable physiological functions in Polo expression and activity at the kinetochores, and disclosed a newin vivofunction for USEs inDrosophila melanogaster.

scholarly journals NCBP2 modulates neurodevelopmental defects of the 3q29 deletion in Drosophila and X. laevis models

2019 ◽  
Author(s):  
Mayanglambam Dhruba Singh ◽  
Matthew Jensen ◽  
Micaela Lasser ◽  
Emily Huber ◽  
Tanzeen Yusuff ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Drosophila Melanogaster ◽  
Xenopus Laevis ◽  
Neurodevelopmental Disorders ◽  
Genetic Interactions ◽  
Brain Morphology ◽  
Cellular Organization ◽  
Biological Mechanisms ◽  
Increased Risk ◽  
Wide Range

ABSTRACTThe 1.6 Mbp deletion on chromosome 3q29 is associated with a range of neurodevelopmental disorders, including schizophrenia, autism, microcephaly, and intellectual disability. Despite its importance towards neurodevelopment, the role of individual genes, genetic interactions, and disrupted biological mechanisms underlying the deletion have not been thoroughly characterized. Here, we used quantitative methods to assay Drosophila melanogaster and Xenopus laevis models with tissue-specific individual and pairwise knockdown of 14 homologs of genes within the 3q29 region. We identified developmental, cellular, and neuronal phenotypes for multiple homologs of 3q29 genes, potentially due to altered apoptosis and cell cycle mechanisms during development. Using the fly eye, we screened for 314 pairwise knockdowns of homologs of 3q29 genes and identified 44 interactions between pairs of homologs and 34 interactions with other neurodevelopmental genes. Interestingly, NCBP2 homologs in Drosophila (Cbp20) and X. laevis (ncbp2) enhanced the phenotypes of homologs of the other 3q29 genes, leading to significant increases in apoptosis that disrupted cellular organization and brain morphology. These cellular and neuronal defects were rescued with overexpression of the apoptosis inhibitors Diap1 and xiap in both models, suggesting that apoptosis is one of several potential biological mechanisms disrupted by the deletion. NCBP2 was also highly connected to other 3q29 genes in a human brain-specific interaction network, providing support for the relevance of our results towards the human deletion. Overall, our study suggests that NCBP2-mediated genetic interactions within the 3q29 region disrupt apoptosis and cell cycle mechanisms during development.AUTHOR SUMMARYRare copy-number variants, or large deletions and duplications in the genome, are associated with a wide range of neurodevelopmental disorders. The 3q29 deletion confers an increased risk for schizophrenia, autism, and microcephaly. To understand the conserved biological mechanisms that are disrupted by this deletion, we systematically tested 14 individual homologs and 314 pairwise interactions of 3q29 genes for neuronal, cellular, and developmental phenotypes in Drosophila melanogaster and Xenopus laevis models. We found that multiple homologs of genes within the deletion region contribute towards developmental defects, such as larval lethality and disrupted cellular organization. Interestingly, we found that NCBP2 acts as a key modifier gene within the region, enhancing the developmental phenotypes of each of the homologs for other 3q29 genes and leading to disruptions in apoptosis and cell cycle pathways. Our results suggest that multiple genes within the 3q29 region interact with each other through shared mechanisms and jointly contribute to neurodevelopmental defects.

scholarly journals Characterization of a Drosophila Centrosome Protein CP309 That Shares Homology with Kendrin and CG-NAP

2004 ◽  
Vol 15 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Shin-ichi Kawaguchi ◽  
Yixian Zheng
Keyword(s):  
Cell Cycle ◽  
Drosophila Melanogaster ◽  
Coiled Coil ◽  
Animal Cells ◽  
Microtubule Nucleation ◽  
Small Complex ◽  
Biochemical Studies ◽  
Ring Complex ◽  
Centrosome Protein

The centrosome in animal cells provides a major microtubule-nucleating site that regulates the microtubule cytoskeleton temporally and spatially throughout the cell cycle. We report the identification in Drosophila melanogaster of a large coiled-coil centrosome protein that can bind to calmodulin. Biochemical studies reveal that this novel Drosophila centrosome protein, centrosome protein of 309 kDa (CP309), cofractionates with the γ-tubulin ring complex and the centrosome-complementing activity. We show that CP309 is required for microtubule nucleation mediated by centrosomes and that it interacts with the γ-tubulin small complex. These findings suggest that the microtubule-nucleating activity of the centrosome requires the function of CP309.

scholarly journals Invadolysin

2004 ◽  
Vol 167 (4) ◽  
pp. 673-686 ◽  
Author(s):  
Brian McHugh ◽  
Sue A. Krause ◽  
Bin Yu ◽  
Anne-Marie Deans ◽  
Sarah Heasman ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Drosophila Melanogaster ◽  
Germ Cells ◽  
Leading Edge ◽  
Mitotic Progression ◽  
Wild Type ◽  
Directed Migration ◽  
New Family ◽  
Cytoplasmic Structures

The cell cycle is widely known to be regulated by networks of phosphorylation and ubiquitin-directed proteolysis. Here, we describe IX-14/invadolysin, a novel metalloprotease present only in metazoa, whose activity appears to be essential for mitotic progression. Mitotic neuroblasts of Drosophila melanogaster IX-14 mutant larvae exhibit increased levels of nuclear envelope proteins, monopolar and asymmetric spindles, and chromosomes that appear hypercondensed in length with a surrounding halo of loosely condensed chromatin. Zymography reveals that a protease activity, present in wild-type larval brains, is missing from homozygous tissue, and we show that IX-14/invadolysin cleaves lamin in vitro. The IX-14/invadolysin protein is predominantly found in cytoplasmic structures resembling invadopodia in fly and human cells, but is dramatically relocalized to the leading edge of migrating cells. Strikingly, we find that the directed migration of germ cells is affected in Drosophila IX-14 mutant embryos. Thus, invadolysin identifies a new family of conserved metalloproteases whose activity appears to be essential for the coordination of mitotic progression, but which also plays an unexpected role in cell migration.

scholarly journals hPOC5 is a centrin-binding protein required for assembly of full-length centrioles

2009 ◽  
Vol 185 (1) ◽  
pp. 101-114 ◽  
Author(s):  
Juliette Azimzadeh ◽  
Polla Hergert ◽  
Annie Delouvée ◽  
Ursula Euteneuer ◽  
Etienne Formstecher ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Drosophila Melanogaster ◽  
Hela Cells ◽  
Binding Protein ◽  
Distal Portion ◽  
S Phase ◽  
G1 Phase ◽  
Evolutionary Divergence ◽  
Distal Half

Centrin has been shown to be involved in centrosome biogenesis in a variety of eukaryotes. In this study, we characterize hPOC5, a conserved centrin-binding protein that contains Sfi1p-like repeats. hPOC5 is localized, like centrin, in the distal portion of human centrioles. hPOC5 recruitment to procentrioles occurs during G2/M, a process that continues up to the full maturation of the centriole during the next cell cycle and is correlated with hyperphosphorylation of the protein. In the absence of hPOC5, RPE1 cells arrest in G1 phase, whereas HeLa cells show an extended S phase followed by cell death. We show that hPOC5 is not required for the initiation of procentriole assembly but is essential for building the distal half of centrioles. Interestingly, the hPOC5 family reveals an evolutionary divergence between vertebrates and organisms like Drosophila melanogaster or Caenorhabditis elegans, in which the loss of hPOC5 may correlate with the conspicuous differences in centriolar structure.

Duration of the cell cycle phases in mutants for the tumor suppressor Merlin in Drosophila melanogaster

2011 ◽  
Vol 47 (4) ◽  
pp. 404-408 ◽  
Author(s):  
T. D. Dubatolova ◽  
N. V. Dorogova ◽  
L. V. Omel’yanchuk ◽  
L. -Sh. Chang
Keyword(s):  
Cell Cycle ◽  
Drosophila Melanogaster ◽  
Tumor Suppressor ◽  
Cell Cycle Phases
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