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Almeida Machado Costa C, Wang XF, Ellsworth C, Deng WM. Polyploidy in development and tumor models in Drosophila. Semin Cancer Biol 2021; 81:106-118. [PMID: 34562587 DOI: 10.1016/j.semcancer.2021.09.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 09/03/2021] [Accepted: 09/18/2021] [Indexed: 12/26/2022]
Abstract
Polyploidy, a cell status defined as more than two sets of genomic DNA, is a conserved strategy across species that can increase cell size and biosynthetic production, but the functional aspects of polyploidy are nuanced and vary across cell types. Throughout Drosophila developmental stages (embryo, larva, pupa and adult), polyploid cells are present in numerous organs and help orchestrate development while contributing to normal growth, well-being and homeostasis of the organism. Conversely, increasing evidence has shown that polyploid cells are prevalent in Drosophila tumors and play important roles in tumor growth and invasiveness. Here, we summarize the genes and pathways involved in polyploidy during normal and tumorigenic development, the mechanisms underlying polyploidization, and the functional aspects of polyploidy in development, homeostasis and tumorigenesis in the Drosophila model.
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Affiliation(s)
- Caique Almeida Machado Costa
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, United States
| | - Xian-Feng Wang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, United States
| | - Calder Ellsworth
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, United States
| | - Wu-Min Deng
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, United States.
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2
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Loganathan R, Kim JH, Wells MB, Andrew DJ. Secrets of secretion-How studies of the Drosophila salivary gland have informed our understanding of the cellular networks underlying secretory organ form and function. Curr Top Dev Biol 2020; 143:1-36. [PMID: 33820619 DOI: 10.1016/bs.ctdb.2020.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Secretory organs are critical for organismal survival. Yet, the transcriptional regulatory mechanisms governing their development and maintenance remain unclear for most model secretory organs. The Drosophila embryonic salivary gland (SG) remedies this deficiency as one of the few organs wherein direct connections from the expression of the early patterning genes to cell specification to organ architecture and functional specialization can be made. Few other models of secretion can be accorded this distinction. Studies from the past three decades have made enormous strides in parsing out the roles of distinct transcription factors (TFs) that direct major steps in furnishing this secretory organ. In the first step of specifying the salivary gland, the activity of the Hox factors Sex combs reduced, Extradenticle, and Homothorax activate expression of fork head (fkh), sage, and CrebA, which code for the major suite of TFs that carry forward the task of organ building and maintenance. Then, in the second key step of building the SG, the program for cell fate maintenance and morphogenesis is deployed. Fkh maintains the secretory cell fate by regulating its own expression and that of sage and CrebA. Fkh and Sage maintain secretory cell viability by actively blocking apoptotic cell death. Fkh, along with two other TFs, Hkb and Rib, also coordinates organ morphogenesis, transforming two plates of precursor cells on the embryo surface into elongated internalized epithelial tubes. Acquisition of functional specialization, the third key step, is mediated by CrebA and Fkh working in concert with Sage and yet another TF, Sens. CrebA directly upregulates expression of all of the components of the secretory machinery as well as other genes (e.g., Xbp1) necessary for managing the physiological stress that inexorably accompanies high secretory load. Secretory cargo specificity is controlled by Sage and Sens in collaboration with Fkh. Investigations have also uncovered roles for various signaling pathways, e.g., Dpp signaling, EGF signaling, GPCR signaling, and cytoskeletal signaling, and their interactions within the gene regulatory networks that specify, build, and specialize the SG. Collectively, studies of the SG have expanded our knowledge of secretory dynamics, cell polarity, and cytoskeletal mechanics in the context of organ development and function. Notably, the embryonic SG has made the singular contribution as a model system that revealed the core function of CrebA in scaling up secretory capacity, thus, serving as the pioneer system in which the conserved roles of the mammalian Creb3/3L-family orthologues were first discovered.
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Affiliation(s)
- Rajprasad Loganathan
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Ji Hoon Kim
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Michael B Wells
- Idaho College of Osteopathic Medicine, Meridian, ID, United States
| | - Deborah J Andrew
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States.
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A Drosophila CRISPR/Cas9 Toolkit for Conditionally Manipulating Gene Expression in the Prothoracic Gland as a Test Case for Polytene Tissues. G3-GENES GENOMES GENETICS 2018; 8:3593-3605. [PMID: 30213867 PMCID: PMC6222582 DOI: 10.1534/g3.118.200539] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Targeting gene function with spatial or temporal specificity is a key goal in molecular genetics. CRISPR-Cas9 has greatly facilitated this strategy, but some standard approaches are problematic. For instance, simple tissue-specific or global overexpression of Cas9 can cause significant lethality or developmental delays even in the absence of gRNAs. In particular, we found that Gal4-mediated expression of UAS-Cas9 in the Drosophila prothoracic gland (PG) was not a suitable strategy to disrupt gene expression, since Cas9 alone caused widespread lethality. The PG is widely used for studying endocrine gland function during animal development, but tools validating PG-specific RNAi phenotypes are lacking. Here, we present a collection of modular gateway-compatible CRISPR-Cas9 tools that allow precise modulation of target gene activity with temporal and spatial specificity. We also demonstrate that Cas9 fused to the progesterone ligand-binding domain can be used to activate gene expression via RU486. Using these approaches, we were able to avoid the lethality associated with simple GAL4-mediated overexpression of Cas9 in the PG. Given that the PG is a polytene tissue, we conclude that these tools work effectively in endoreplicating cells where Cas9 has to target multiple copies of the same locus. Our toolkit can be easily adapted for other tissues and can be used both for gain- and loss-of-function studies.
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Spradling AC. Polytene Chromosome Structure and Somatic Genome Instability. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2017; 82:293-304. [PMID: 29167281 DOI: 10.1101/sqb.2017.82.033670] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Polytene chromosomes have for 80 years provided the highest resolution view of interphase genome structure in an animal cell nucleus. These chromosomes represent the normal genomic state of nearly all Drosophila larval and many adult cells, and a better understanding of their striking banded structure has been sought for decades. A more recently appreciated characteristic of Drosophila polytene cells is somatic genome instability caused by unfinished replication (UR). Repair of stalled forks generates enough deletions in polytene salivary gland cells to alter 10%-90% of the DNA strands within more than 100 UR regions comprising 20% of the euchromatic genome. We accurately map UR regions and show that most approximate large polytene bands, indicating that replication forks frequently stall near band boundaries in late S phase. Chromosome conformation capture has recently identified dense topologically associated domains (TADs) in many genomes and most UR bands are similar or slightly smaller than a cognate Drosophila TAD. We argue that bands serve the evolutionarily ancient function of coordinating genome replication with local gene activity. We also discuss the relatively recent evolution of polyteny and somatic instability in Diptera and propose that these processes helped propel the amazing success of two-winged flies in becoming the most ecologically diverse insect group, with 200 times the number of species as mammals.
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Affiliation(s)
- Allan C Spradling
- Department of Embryology, Howard Hughes Medical Institute, Carnegie Institution for Science, Baltimore, Maryland 21218
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5
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Kinney NA, Sharakhov IV, Onufriev AV. Investigation of the chromosome regions with significant affinity for the nuclear envelope in fruit fly--a model based approach. PLoS One 2014; 9:e91943. [PMID: 24651400 PMCID: PMC3961273 DOI: 10.1371/journal.pone.0091943] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 02/18/2014] [Indexed: 12/16/2022] Open
Abstract
Three dimensional nuclear architecture is important for genome function, but is still poorly understood. In particular, little is known about the role of the “boundary conditions” – points of attachment between chromosomes and the nuclear envelope. We describe a method for modeling the 3D organization of the interphase nucleus, and its application to analysis of chromosome-nuclear envelope (Chr-NE) attachments of polytene (giant) chromosomes in Drosophila melanogaster salivary glands. The model represents chromosomes as self-avoiding polymer chains confined within the nucleus; parameters of the model are taken directly from experiment, no fitting parameters are introduced. Methods are developed to objectively quantify chromosome territories and intertwining, which are discussed in the context of corresponding experimental observations. In particular, a mathematically rigorous definition of a territory based on convex hull is proposed. The self-avoiding polymer model is used to re-analyze previous experimental data; the analysis suggests 33 additional Chr-NE attachments in addition to the 15 already explored Chr-NE attachments. Most of these new Chr-NE attachments correspond to intercalary heterochromatin – gene poor, dark staining, late replicating regions of the genome; however, three correspond to euchromatin – gene rich, light staining, early replicating regions of the genome. The analysis also suggests 5 regions of anti-contact, characterized by aversion for the NE, only two of these correspond to euchromatin. This composition of chromatin suggests that heterochromatin may not be necessary or sufficient for the formation of a Chr-NE attachment. To the extent that the proposed model represents reality, the confinement of the polytene chromosomes in a spherical nucleus alone does not favor the positioning of specific chromosome regions at the NE as seen in experiment; consequently, the 15 experimentally known Chr-NE attachment positions do not appear to arise due to non-specific (entropic) forces. Robustness of the key conclusions to model assumptions is thoroughly checked.
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Affiliation(s)
- Nicholas Allen Kinney
- Genomics Bioinformatics and Computational Biology, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Igor V. Sharakhov
- Department of Entomology, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail: (IVS); (AVO)
| | - Alexey V. Onufriev
- Department of Physics, Virginia Tech, Blacksburg, Virginia, United States of America
- Department of Computer Science, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail: (IVS); (AVO)
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6
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Belmont AS. Large-scale chromatin organization: the good, the surprising, and the still perplexing. Curr Opin Cell Biol 2013; 26:69-78. [PMID: 24529248 DOI: 10.1016/j.ceb.2013.10.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 10/07/2013] [Accepted: 10/15/2013] [Indexed: 11/19/2022]
Abstract
Traditionally large-scale chromatin structure has been studied by microscopic approaches, providing direct spatial information but limited sequence context. In contrast, newer 3C (chromosome capture conformation) methods provide rich sequence context but uncertain spatial context. Recent demonstration of large, topologically linked DNA domains, hundreds to thousands of kb in size, may now link 3C data to actual chromosome physical structures, as visualized directly by microscopic methods. Yet, new data suggesting that 3C may measure cytological rather than molecular proximity prompts a renewed focus on understanding the origin of 3C interactions and dissecting the biological significance of long-range genomic interactions.
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Affiliation(s)
- Andrew S Belmont
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, B107 CLSL, 601 South Goodwin Avenue, Urbana, IL 61801, United States.
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7
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Zhimulev IF, Belyaeva ES, Vatolina TY, Demakov SA. Banding patterns in Drosophila melanogaster polytene chromosomes correlate with DNA-binding protein occupancy. Bioessays 2012; 34:498-508. [PMID: 22419120 DOI: 10.1002/bies.201100142] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The most enigmatic feature of polytene chromosomes is their banding pattern, the genetic organization of which has been a very attractive puzzle for many years. Recent genome-wide protein mapping efforts have produced a wealth of data for the chromosome proteins of Drosophila cells. Based on their specific protein composition, the chromosomes comprise two types of bands, as well as interbands. These differ in terms of time of replication and specific types of proteins. The interbands are characterized by their association with "active" chromatin proteins, nucleosome remodeling, and origin recognition complexes, and so they have three functions: acting as binding sites for RNA pol II, initiation of replication and nucleosome remodeling of short fragments of DNA. The borders and organization of the same band and interband regions are largely identical, irrespective of the cell type studied. This demonstrates that the banding pattern is a universal principle of the organization of interphase polytene and non-polytene chromosomes.
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Affiliation(s)
- Igor F Zhimulev
- Institute of Molecular and Cellular Biology, Siberian Division of Russian Academy of Sciences, Novosibirsk, Russia.
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9
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Nordman J, Li S, Eng T, MacAlpine D, Orr-Weaver TL. Developmental control of the DNA replication and transcription programs. Genome Res 2011; 21:175-81. [PMID: 21177957 PMCID: PMC3032921 DOI: 10.1101/gr.114611.110] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 10/26/2010] [Indexed: 01/03/2023]
Abstract
Polyploid or polytene cells, which have more than 2C DNA content, are widespread throughout nature and present in most differentiated Drosophila tissues. These cells also can display differential replication, that is, genomic regions of increased or decreased DNA copy number relative to overall genomic ploidy. How frequently differential replication is used as a developmental strategy remains unclear. Here, we use genome-wide array-based comparative genomic hybridization (aCGH) to profile differential DNA replication in isolated and purified larval fat body and midgut tissues of Drosophila, and we compare them with recent aCGH profiles of the larval salivary gland. We identify sites of euchromatic underreplication that are common to all three tissues and others that are tissue specific. We demonstrate that both common and tissue-specific underreplicated sites are dependent on the Suppressor of Underreplication protein, SUUR. mRNA-seq profiling shows that whereas underreplicated regions are generally transcriptionally silent in the larval midgut and salivary gland, transcriptional silencing and underreplication have been uncoupled in the larval fat body. In addition to revealing the prevalence of differential replication, our results show that transcriptional silencing and underreplication can be mechanistically uncoupled.
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Affiliation(s)
- Jared Nordman
- Whitehead Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Sharon Li
- Whitehead Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Thomas Eng
- Whitehead Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - David MacAlpine
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Terry L. Orr-Weaver
- Whitehead Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
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10
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Chen B, Shilova VY, Zatsepina OG, Evgen’ev MB, Feder ME. Location of P element insertions in the proximal promoter region of Hsp70A is consequential for gene expression and correlated with fecundity in Drosophila melanogaster. Cell Stress Chaperones 2008; 13:11-7. [PMID: 18347937 PMCID: PMC2666209 DOI: 10.1007/s12192-007-0002-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Revised: 06/15/2007] [Accepted: 06/22/2007] [Indexed: 01/29/2023] Open
Abstract
We compared a series of Drosophila strains with P element insertions from -28 to -144 nucleotides 5' to the transcription start site of the Hsp70A genes-corresponding to the range of naturally occurring P element insertion sites-to elucidate the consequences of insertion site for Hsp70A gene expression. Although all insertions reduced Hsp70A expression below that of a control strain, the magnitude of the reduction was inversely related to the number of nucleotides between the transcription start site and the insertion site. A pre-existing hypothesis is that naturally occurring transposable element insertions in Hsp promoters may be beneficial in some circumstances, which may account for their retention in natural populations. In the present study, in a control line heat shock reduced fecundity, whereas in lines with P element insertions heat shock typically increased fecundity. Finally, according to cluster-specific quantitative RT-PCR, expression of the Hsp70A cluster genes was typically greater than that of the Hsp70B gene cluster genes, although the latter are more numerous and, in this case, free of P element insertions.
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Affiliation(s)
- Bing Chen
- Department of Organismal Biology and Anatomy, The University of Chicago, 1027 E. 57th Street, Chicago, IL 60637 USA
- Institute of Zoology, Chinese Academy of Sciences, Beijing, 100080 China
| | - Victoria Y. Shilova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 117984 Moscow, Russia
| | - Olga G. Zatsepina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 117984 Moscow, Russia
| | - Michael B. Evgen’ev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 117984 Moscow, Russia
| | - Martin E. Feder
- Department of Organismal Biology and Anatomy, The University of Chicago, 1027 E. 57th Street, Chicago, IL 60637 USA
- The Committees on Evolutionary Biology, Genetics, and Molecular Medicine, The University of Chicago, 1027 E. 57th Street, Chicago, IL 60637 USA
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11
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Affiliation(s)
- I F Zhimulev
- Institute of Cytology and Genetics, Siberian Division of Russian Academy of Sciences, Novosibirsk, Russia
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12
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Zhimulev IF. Polytene chromosomes, heterochromatin, and position effect variegation. ADVANCES IN GENETICS 1997; 37:1-566. [PMID: 9352629 DOI: 10.1016/s0065-2660(08)60341-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- I F Zhimulev
- Institute of Cytology and Genetics, Siberian Division of the Russian Academy of Sciences, Novosibirsk, Russia
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13
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Zhao K, Harel A, Stuurman N, Guedalia D, Gruenbaum Y. Binding of matrix attachment regions to nuclear lamin is mediated by the rod domain and depends on the lamin polymerization state. FEBS Lett 1996; 380:161-4. [PMID: 8603728 DOI: 10.1016/0014-5793(96)00034-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The nuclear matrix maintains specific interactions with genomic DNA at sites known as matrix attachment regions (M/SARs). M/SARs bind in vitro to lamin polymers. We show that the polymerized alpha-helical rod domain of lamin Dm0 provides by itself the specific binding to the ftz M/SAR. In contrast, unpolymerized rod domain does not bind specifically to this M/SAR. Non-specific binding to DNA is also observed with Dm0 containing a point mutation that impairs its ability to polymerize or with the isolated tail domain. These data suggest that the specific binding of lamins to M/SARs requires the rod domain and depends on the lamin polymerization state.
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Affiliation(s)
- K Zhao
- Department of Genetics, Life Sciences Institute, Hebrew University of Jerusalem, Israel
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14
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15
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Mal'ceva NI, Gyurkovics H, Zhimulev IF. General characteristics of the polytene chromosome from ovarian pseudonurse cells of the Drosophila melanogaster otu11 and fs(2)B mutants. Chromosome Res 1995; 3:191-200. [PMID: 7780663 DOI: 10.1007/bf00710713] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Polytene chromosomes of good cytological quality from pseudonurse cells (PNCs) of fs(2)B and otu11 mutants were obtained, photomaps for otu11 mutants were constructed and the general characteristics of polytene chromosomes from salivary glands (SGs) and PNCs were compared. Three conditions were found to improve the cytological quality of PNC chromosomes: temperature below 18 degrees C, a protein-rich medium and presence of the Y-chromosome. Detailed comparison of the chromosome banding pattern from SGs and PNCs has shown only minor differences between them. The frequency of asynapsis appeared to be 10 times higher for PNC chromosomes. Despite previous reports, features such as breaks and ectopic contacts turned out to be also typical for PNC chromosomes, but with remarkably lower frequencies.
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Affiliation(s)
- N I Mal'ceva
- Laboratory of Molecular Cytogenetics, Siberian Division of Russian Academy of Sciences, Novosibirsk
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16
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Lakhotia SC, Sharma A. RNA metabolism in situ at the 93D heat shock locus in polytene nuclei of Drosophila melanogaster after various treatments. Chromosome Res 1995; 3:151-61. [PMID: 7540096 DOI: 10.1007/bf00710708] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Quantitative in situ hybridization to RNA on polytene chromosome spreads, using the 93D exon-, intron- and repeat-specific 35S-labeled antisense RNA probes, revealed treatment- (heat shock, benzamide, colchicine, heat shock followed by benzamide and heat shock in the presence of colchicine) specific differences in the metabolism (synthesis and/or accumulation at the puff site) of the various hsr-omega transcripts, namely hsr-omega-nuclear (omega-n), omega-pre-cytoplasmic (omega-pre-c) and omega-cytoplasmic (omega-c). While heat shock increased the levels of all the three transcripts at the 93D puff site in a coordinated manner, benzamide led to a significant increase in the levels of hsr-omega-n and pre-c; on the other hand, colchicine caused increased levels of the omega-n and omega-c RNA species at 93D. The results also suggested splicing of hsr-omega-pre-c RNA at the site of synthesis with the spliced-out 'free' intron (hsr-omega-fi) accumulating at the puff site. The rate of splicing and/or turnover of the hsr-omega-fi varied in a treatment-specific manner. Although a combined treatment to salivary glands with heat shock and benzamide or colchicine is known to inhibit puffing and [3H]uridine incorporation at 93D, the two treatments resulted in a treatment-specific increase in the in situ levels of different hsr-omega transcripts at the 93D site, suggesting a reduced turnover of specific transcripts from the site under these conditions. We suggest that the different 93D transcripts have roles in turnover and/or transport of RNA in nucleus as well as some role in cytoplasmic translation.
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Affiliation(s)
- S C Lakhotia
- Department of Zoology, Banaras Hindu University, Varanasi, India
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17
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Heino TI. Polytene chromosomes from ovarian pseudonurse cells of the Drosophila melanogaster otu mutant. II. Photographic map of the X chromosome. Chromosoma 1994; 103:4-15. [PMID: 8013253 DOI: 10.1007/bf00364721] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The banding pattern of the polytene chromosomes of the ovarian pseudonurse cells (PNC) of the Drosophila melanogaster otu mutant were compared with larval salivary gland (SG) polytene chromosomes. The X chromosome was studied and no significant differences were found in the banding pattern between these functionally very different tissues. Most of the differences result from differential puffing activity. In situ hybridisation with five different DNA probes located along the X chromosome was used to cross-check the results obtained by morphological mapping. The constrictions present in the SG chromosomes were found to be absent in the germ line derived PNC chromosomes. There are prominent puffs in the PNC chromosomes at certain locations where genes known to be transcriptionally active in the germ line reside. This suggests that at least some of the genes active in the wild-type nurse cells may also be active in the PNC cells.
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Affiliation(s)
- T I Heino
- Department of Genetics, University of Helsinki, Finland
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18
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Affiliation(s)
- M L Pardue
- Department of Biology, Massachusetts Institute of Technology, Cambridge 02139
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19
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Mavragani-Tsipidou P, Scouras ZG. Developmental changes in fat body and midgut chromosomes of Drosophila auraria. Chromosoma 1991; 100:443-52. [PMID: 1914663 DOI: 10.1007/bf00364555] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Changes in puffing activity of fat body (FB) and midgut (MG) chromosomes of Drosophila auraria during late larval and white prepupal development as well as after in vitro culture with or without ecdysterone were studied and compared with those of the salivary gland (SG). The Balbiani Rings characteristic of the SG chromosomes of D. auraria, are not formed in FB and MG. Most of the inverted tandem chromosomal duplications that have been found to be common to all three tissues showed differentiation of puffing activity of the bands considered to be homologous. The major early ecdysone puffs 73A and 73B (considered to be homologues of D. melanogaster puffs 74EF and 75B, respectively), together with other early ecdysone puffs were present in all three tissues. Clear intermoult and postintermoult puffs were not evident in FB and MG chromosomes. However, a small set of late ecdysone puffs could be scored in FB, while no late ecdysone puffs were abserved in MG. Other tissue-specific puffs were identified, but a very small number of them were limited to MG.
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Affiliation(s)
- P Mavragani-Tsipidou
- Department of Genetics, Development and Molecular Biology, School of Biology, Faculty of Sciences, Aristotelian University of Thessaloniki, Greece
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20
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Lakhotia SC, Chowdhuri DK, Burma PK. Mutations affecting beta-alanine metabolism influence inducibility of the 93D puff by heat shock in Drosophila melanogaster. Chromosoma 1990; 99:296-305. [PMID: 2119984 DOI: 10.1007/bf01731706] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Effect of mutations at the ebony or black locus on induction of heat shock puffs in polytene nuclei of salivary glands of Drosophila melanogaster larvae were examined by [3H]uridine autoradiography. The levels of beta-alanine in the body are known to be increased by mutation at the ebony locus but decreased by mutation at the black locus. The presence of mutant allele/s at either locus in the homo- or heterozygous condition prevented induction of the 93D puff by heat shock. Elimination of the mutant allele at the ebony or black locus by recombination or by reversion of a P element insertion mutant allele of ebony restored the heat shock inducibility of the 93D puff. In vivo or in vitro administration of excess beta-alanine to salivary glands of wild-type larvae also resulted in the 93D site being refractory to heat shock induction. In agreement with earlier results, non-induction of the 93D puff during heat shock due to the beta-alanine effect was accompanied by unequal puffing of the 87A and 87C loci. The selective inducibility of the 93D puff by benzamide was not affected by ebony or black mutations or by excess beta-alanine in wild-type larvae.
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Affiliation(s)
- S C Lakhotia
- Department of Zoology, Banaras Hindu University, Varanasi, India
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21
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Heino TI. Polytene chromosomes from ovarian pseudonurse cells of the Drosophila melanogaster otu mutant. I. Photographic map of chromosome 3. Chromosoma 1989; 97:363-73. [PMID: 2498045 DOI: 10.1007/bf00292763] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Certain mutant alleles of the otu locus in Drosophila melanogaster produce abnormal nurse cells in the ovaries. These cells are called pseudonurse cells (PNC), since they generate polytene chromosomes instead of endopolyploid ones and do not normally have an oocyte to nurse. The banding pattern of polytene chromosome 3 from the salivary glands (SG) and from PNCs of homozygous otu1 females was compared and a detailed photomap of PNC chromosomes with different degrees of polyteny is presented. The banding pattern was found to be strikingly similiar in the two tissues. The puffing pattern of the PNC chromosomes is discussed. No constrictions or breaks were found in the PNC chromosomes which seems to indicate that these sites, which are known to be underreplicated in the SG chromosomes, are equally replicated along with the rest of the chromosomes in the PNC nuclei.
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Affiliation(s)
- T I Heino
- Department of Genetics, University of Helsinki, Finland
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22
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Abstract
In Drosophila gibberosa, differences between midgut and salivary gland chromosomes fall into two categories: tissue-specific band modulations which persist throughout the 90 h developmental period that we studied and tissue-specific puffs. Puffs that are common to both tissues tend to appear earlier in the midgut. Some major early ecdysteroid-induced puffs appear simultaneously in both tissues at the end of the third larval instar; however, the many late puffs that follow in the salivary glands are absent from the midgut. Intense puff activity in the early third larval instar midgut declines at the time of the hormonal pulse that initiates intense gene and secretory activity in salivary glands; the sloughing of midgut cells ensues.
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Affiliation(s)
- P A Roberts
- Department of Zoology, Oregon State University, Corvallis 97333
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23
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Visa N, Gonzàlez-Duarte R, Santa-Cruz MC. A cytological and molecular analysis of Adh gene expression in Drosophila melanogaster polytene chromosomes. Chromosoma 1988; 97:171-7. [PMID: 2465876 DOI: 10.1007/bf00327375] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Analysis of puffing patterns in Drosophila melanogaster salivary gland chromosomes indicates the existence of a developmentally specific puff in the 35B region. This puff seems to originate from bands 35B2 or 35B3, where Adh is located, and it is expanded in more than 60% of the nuclei examined. The presence of RNA polymerase II in this puff as well as its ability to incorporate tritiated uridine shows that it corresponds to a transcriptionally active site. RNA blotting and in situ hybridization experiments indicate that Adh is transcribed, although not very actively, in salivary glands during the third larval instar. However, this tissue does not display detectable levels of ADH activity. By contrast, we have found that in midgut polytene chromosomes the 35B region is not visibly puffed in spite of the high levels of Adh transcripts detected. These results seem to suggest that puffing at the 35B region could be mainly promoted by genes closely linked to Adh, possibly with a minor contribution of this gene.
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Affiliation(s)
- N Visa
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Spain
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