Ultrabithorax and the control of cell morphology in Drosophila halteres

Development ◽  
2000 ◽  
Vol 127 (1) ◽  
pp. 97-107 ◽  
Author(s):  
F. Roch ◽  
M. Akam
Keyword(s):  
Cell Morphology ◽  
Hind Wing ◽  
Ectopic Expression ◽  
Apical Surface ◽  
Pupal Development ◽  
After Puparium Formation ◽  
Differential Development ◽  
Downstream Effects ◽  
Pupal Wing ◽  
Puparium Formation

The Drosophila haltere is a much reduced and specialised hind wing, which functions as a balance organ. Ultrabithorax (Ubx) is the sole Hox gene responsible for the differential development of the fore-wing and haltere in Drosophila. Previous work on the downstream effects of Ubx has focused on the control of pattern formation. Here we provide the first detailed description of cell differentiation in the haltere epidermis, and of the developmental processes that distinguish wing and haltere cells. By the end of pupal development, haltere cells are 8-fold smaller in apical surface area than wing cells; they differ in cell outline, and in the size and number of cuticular hairs secreted by each cell. Wing cells secrete only a thin cuticle, and undergo apoptosis within 2 hours of eclosion. Haltere cells continue to secrete cuticle after eclosion. Differences in the shape of wing and haltere cells reflect differences in the architecture of the actin cytoskeleton that become apparent between 24 and 48 hours after puparium formation. We show that Ubx protein is not needed later than 6 hours after puparium formation to specify these differences, though it is required at later stages for the correct development of campaniform sensilla on the haltere. We conclude that, during normal development, Ubx protein expressed before pupation controls a cascade of downstream effects that control changes in cell morphology 24–48 hours later. Ectopic expression of Ubx in the pupal wing, up to 30 hours after puparium formation, can still elicit many aspects of haltere cell morphology. The response of wing cells to Ubx at this time is sensitive to both the duration and level of Ubx exposure.

scholarly journals The MAL Proteolipid Is Necessary for Normal Apical Transport and Accurate Sorting of the Influenza Virus Hemagglutinin in Madin-Darby Canine Kidney Cells

1999 ◽  
Vol 145 (1) ◽  
pp. 141-151 ◽  
Author(s):  
Rosa Puertollano ◽  
Fernando Martín-Belmonte ◽  
Jaime Millán ◽  
María del Carmen de Marco ◽  
Juan P. Albar ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Mdck Cells ◽  
Basolateral Membrane ◽  
Ectopic Expression ◽  
Apical Surface ◽  
Madin Darby Canine Kidney ◽  
Transport Pathway ◽  
Influenza Virus Hemagglutinin ◽  
Darby Canine Kidney ◽  
Canine Kidney

The MAL (MAL/VIP17) proteolipid is a nonglycosylated integral membrane protein expressed in a restricted pattern of cell types, including T lymphocytes, myelin-forming cells, and polarized epithelial cells. Transport of the influenza virus hemagglutinin (HA) to the apical surface of epithelial Madin-Darby canine kidney (MDCK) cells appears to be mediated by a pathway involving glycolipid- and cholesterol- enriched membranes (GEMs). In MDCK cells, MAL has been proposed previously as being an element of the protein machinery for the GEM-dependent apical transport pathway. Using an antisense oligonucleotide-based strategy and a newly generated monoclonal antibody to canine MAL, herein we have approached the effect of MAL depletion on HA transport in MDCK cells. We have found that MAL depletion diminishes the presence of HA in GEMs, reduces the rate of HA transport to the cell surface, inhibits the delivery of HA to the apical surface, and produces partial missorting of HA to the basolateral membrane. These effects were corrected by ectopic expression of MAL in MDCK cells whose endogenous MAL protein was depleted. Our results indicate that MAL is necessary for both normal apical transport and accurate sorting of HA.

scholarly journals Inhibition of Anchorage-independent Growth of Transformed NIH3T3 Cells by Epithelial Protein Lost in Neoplasm (EPLIN) Requires Localization of EPLIN to Actin Cytoskeleton

2002 ◽  
Vol 13 (4) ◽  
pp. 1408-1416 ◽  
Author(s):  
Yuhong Song ◽  
Raymond S. Maul ◽  
C. Sachi Gerbin ◽  
David D. Chang
Keyword(s):  
Actin Cytoskeleton ◽  
Cell Morphology ◽  
Ectopic Expression ◽  
Growth Control ◽  
Terminal Region ◽  
Transformed Cells ◽  
Lim Domain ◽  
Nih3t3 Cells ◽  
Anchorage Independent Growth ◽  
Dependent Growth

Epithelial protein lost in neoplasm (EPLIN) is a cytoskeleton-associated protein characterized by the presence of a single centrally located lin-11, isl-1, and mec-3 (LIM) domain. We have reported previously that EPLIN is down-regulated in transformed cells. In this study, we have investigated whether ectopic expression of EPLIN affects transformation. In untransformed NIH3T3 cells, retroviral-mediated transduction of EPLIN did not alter the cell morphology or growth. NIH3T3 cells expressing EPLIN, however, failed to form colonies when transformed by the activated Cdc42 or the chimeric nuclear oncogene EWS/Fli-1. This suppression of anchorage-independent growth was not universal because EPLIN failed to inhibit the colony formation of Ras-transformed cells. Interestingly, the localization of EPLIN to the actin cytoskeleton was maintained in the EWS/Fli-1– or Cdc42-transformed cells, but not in Ras-transformed cells where it was distributed heterogeneously in the cytoplasm. Using truncated EPLIN constructs, we demonstrated that the NH2-terminal region of EPLIN is necessary for both the localization of EPLIN to the actin cytoskeleton and suppression of anchorage-independent growth of EWS/Fli-1–transformed cells. The LIM domain or the COOH-terminal region of EPLIN could be deleted without affecting its cytoskeletal localization or ability to suppress anchorage-dependent growth. Our study indicates EPLIN may function in growth control by associating with and regulating the actin cytoskeleton.

scholarly journals Activation of latent ribonuclease in the fat-body of fleshfly (Sarcophaga peregrina) larvae on pupation

1981 ◽  
Vol 196 (3) ◽  
pp. 699-703 ◽  
Author(s):  
Y Aoki ◽  
S Natori
Keyword(s):  
Crude Extract ◽  
Fat Body ◽  
Inhibitor Protein ◽  
After Puparium Formation ◽  
Inhibitor Complex ◽  
Puparium Formation ◽  
Fat Bodies ◽  
Third Instar Larvae

A crude extract of the fat-bodies of third-instar larvae of Sarcophaga peregrina (fleshfly) was found to contain latent RNAase (ribonuclease) consisting of RNAase and inhibitor protein that is sensitive to p-chloromercuribenzoic acid. The RNAase activity in the crude extract of fat-bodies became detectable with time after puparium formation, indicating that the inhibitor is selectively inactivated and RNAase is released from the RNAase-inhibitor complex during metamorphosis.

scholarly journals Pitx2a Expression Alters Actin-Myosin Cytoskeleton and Migration of HeLa Cells through Rho GTPase Signaling

2002 ◽  
Vol 13 (2) ◽  
pp. 683-697 ◽  
Author(s):  
Qize Wei ◽  
Robert S. Adelstein
Keyword(s):  
Cell Morphology ◽  
Hela Cells ◽  
Rho Gtpase ◽  
Expression System ◽  
Ectopic Expression ◽  
Cell Spreading ◽  
Dominant Negative ◽  
Nucleotide Exchange ◽  
Cell Contacts ◽  
Cell Cell

We ectopically expressed the transcription factor Pitx2a, one of the Pitx2 isoforms, in HeLa cells by using a tetracycline-inducible expression system and examined whether Pitx2a was capable of modulating Rho GTPase signaling and altering the cell's cytoskeleton. Ectopic expression of Pitx2a induced actin-myosin reorganization, leading to increased cell spreading, suppression of cell migration, and the strengthening of cell-cell adhesion, marked by the accumulation and localization of β-catenin and N-cadherin to the sites of cell-cell contacts. Moreover, Pitx2a expression resulted in activation of the Rho GTPases Rac1 and RhoA, and the dominant negative Rac1 mutant N17Rac1 inhibited cell spreading and disrupted localization of β-catenin to the sites of cell-cell contacts. Both reorganization of actin-myosin and cell spreading require phosphatidylinositol 3-kinase activity, which is also necessary for activation of the Rho GTPase proteins. Pitx2a induced the expression of Trio, a guanine nucleotide exchange factor for Rac1 and RhoA, which preceded cell spreading, and the expression of Trio protein was down-regulated after the changes in cell spreading and cell morphology were initiated. In addition, Pitx2a also induces cell cycle arrest at G0/G1, most likely due to the accumulation of the tumor suppressor proteins p53 and p21. Our data indicate that the transcriptional activities initiated in the nucleus by Pitx2a result in profound changes in HeLa cell morphology, migration, and proliferation.

scholarly journals Temperature Effects on Day Old Drosophila Pupae

1962 ◽  
Vol 45 (4) ◽  
pp. 777-799 ◽  
Author(s):  
Roger Milkman
Keyword(s):  
Protein Denaturation ◽  
Biological Effects ◽  
Interspecific Variation ◽  
Temperature Adaptation ◽  
After Puparium Formation ◽  
Present Context ◽  
Rapid Temperature ◽  
Puparium Formation ◽  
Elliptical Holes

Day old Drosophila pupae were subjected to a variety of closely controlled temperature shocks. Twenty-five hours after puparium formation (at 23°), temperatures from 39.5–41.5° (Q1 = 2.3) differentially disturb the formation of the posterior crossvein. Three other separate treatments disturb posterior crossvein formation: treatments in the range 36.0–37.0° at 25 hours; 37.3–37.8° at 25 hours; and 39.5–41.5° at 19 hours. Certain qualitative effects are associated with certain temperatures: elliptical holes are seen in wings of flies exposed 25 hours after puparium formation to temperatures from 37.3–37.8°. Anterior crossvein defects ensue if animals are similarly exposed to temperatures from 37.9–38.2°. Within the physiological range, animals raised at higher temperatures are more resistant to the effects of temperatures at 39.5–41.5°. An extremely rapid temperature adaptation by exposures to temperatures in the range 31–38° results in markedly greater resistance to heat shock; here resistance to production of crossvein defects increases faster than to death. The association between qualitative effects and treatment temperatures is modified by changing the temperature at which the animals spend their first day of pupal life. Summation experiments support conclusions drawn from the simpler experiments. Genetic variation and interspecific variation are discussed in the present context, as well as implications of the role of protein denaturation in the biological effects of high temperatures and further, more general experiments.

scholarly journals Synaptogenesis in the giant-fibre system of Drosophila: interaction of the giant fibre and its major motorneuronal target

Development ◽  
2000 ◽  
Vol 127 (23) ◽  
pp. 5203-5212
Author(s):  
K. Jacobs ◽  
M.G. Todman ◽  
M.J. Allen ◽  
J.A. Davies ◽  
J.P. Bacon
Keyword(s):  
Fluorescent Protein ◽  
Lucifer Yellow ◽  
Active Form ◽  
Dye Coupling ◽  
Electrical Synapses ◽  
Giant Fibre ◽  
High Resolution Data ◽  
After Puparium Formation ◽  
Puparium Formation ◽  
Giant Fibre System

The tergotrochanteral (jump) motorneuron is a major synaptic target of the Giant Fibre in Drosophila. These two neurons are major components of the fly's Giant-Fibre escape system. Our previous work has described the development of the Giant Fibre in early metamorphosis and the involvement of the shaking-B locus in the formation of its electrical synapses. In the present study, we have investigated the development of the tergotrochanteral motorneuron and its electrical synapses by transforming Drosophila with a Gal4 fusion construct containing sequences largely upstream of, but including, the shaking-B(lethal) promoter. This construct drives reporter gene expression in the tergotrochanteral motorneuron and some other neurons. Expression of green fluorescent protein in the motorneuron allows visualization of its cell body and its subsequent intracellular staining with Lucifer Yellow. These preparations provide high-resolution data on motorneuron morphogenesis during the first half of pupal development. Dye-coupling reveals onset of gap-junction formation between the tergotrochanteral motorneuron and other neurons of the Giant-Fibre System. The medial dendrite of the tergotrochanteral motorneuron becomes dye-coupled to the peripheral synapsing interneurons between 28 and 32 hours after puparium formation. Dye-coupling between tergotrochanteral motorneuron and Giant Fibre is first seen at 42 hours after puparium formation. All dye coupling is abolished in a shaking-B(neural) mutant. To investigate any interactions between the Giant Fibre and the tergotroachanteral motorneuron, we arrested the growth of the motorneuron's medial neurite by targeted expression of a constitutively active form of Dcdc42. This results in the Giant Fibre remaining stranded at the midline, unable to make its characteristic bend. We conclude that Giant Fibre morphogenesis normally relies on fasciculation with its major motorneuronal target.

scholarly journals The development of the bristles in normal and some mutant types of Drosophila melanogaster

1942 ◽  
Vol 131 (862) ◽  
pp. 87-110 ◽  
Keyword(s):  
Drosophila Melanogaster ◽  
Single Cell ◽  
Epidermal Cells ◽  
After Puparium Formation ◽  
Puparium Formation ◽  
Tormogen Cell

This paper describes the development of the normal macro- and micro-chaetae of Drosophila , together with that of twelve mutant types. The phenotypes of twenty combinations of these genes have been studied. Each normal bristle is secreted by a single cell, the trichogen, which lies beneath a tormogen cell which secretes a socket. These bristle cells are first distinguishable in the epidermis at about 15 hr. after puparium formation, when they have already divided to form a pair, and are slightly larger than the normal epidermal cells. The secretion of the bristle proceeds most rapidly between 30 and 55 hr., during which time the bristle cells are very large and obviously highly polyploid. The socket, apparently, does not completely enclose the base of the bristle in the earliest stages. The development of the microchaetae is essentially similar to that of the macrochaetae. The actions of the twelve genes can be summarized as follows: Scute causes a primary absence of certain bristle cells, and extra-bristle-complex -41 e and hairy the presence of supernumerary groups. Split frequently causes an extra division, so that a group of four cells is formed; these may be arranged as two trichogens and two tormogens, or one trichogen and three tormogens; or the whole group may fail to reach the surface of the epithelium, when no bristle or socket is formed. Dichaete may produce an effect similar to the last-described of split , and it may also cause an extra division of the trichogen, producing a double bristle in a single socket. Hairless causes the trichogens of some bristle groups to lie level with the tormogens, and to develop like them into sockets. In Stubble the tormogens are shifted rather to one side of the trichogens, so that the bristle is less closely invested by the socket, and becomes thicker and shorter. In shaven-naked the trichogen is irregularly displaced, becoming more or less converted into a tormogen; the small bristle which may be secreted is often peculiarly fanned out at the tip, suggesting an effect of the gene on the nature of the material secreted. Spineless and morula slow down the growth of the bristle cells. Singed, forked and Bristle all affect the nature of the bristle secretion, there being some reason to suggest that the effects of Bristle and singed may be similar and different to that of forked.

Development of the Drosophila mushroom bodies: sequential generation of three distinct types of neurons from a neuroblast

Development ◽  
1999 ◽  
Vol 126 (18) ◽  
pp. 4065-4076 ◽  
Author(s):  
T. Lee ◽  
A. Lee ◽  
L. Luo
Keyword(s):  
Single Cell ◽  
Larval Stage ◽  
Mushroom Body ◽  
Molecular Mechanisms ◽  
Developmental Stages ◽  
Mushroom Bodies ◽  
After Puparium Formation ◽  
Body Development ◽  
Drosophila Brain ◽  
Puparium Formation

The mushroom bodies (MBs) are prominent structures in the Drosophila brain that are essential for olfactory learning and memory. Characterization of the development and projection patterns of individual MB neurons will be important for elucidating their functions. Using mosaic analysis with a repressible cell marker (Lee, T. and Luo, L. (1999) Neuron 22, 451–461), we have positively marked the axons and dendrites of multicellular and single-cell mushroom body clones at specific developmental stages. Systematic clonal analysis demonstrates that a single mushroom body neuroblast sequentially generates at least three types of morphologically distinct neurons. Neurons projecting into the (gamma) lobe of the adult MB are born first, prior to the mid-3rd instar larval stage. Neurons projecting into the alpha' and beta' lobes are born between the mid-3rd instar larval stage and puparium formation. Finally, neurons projecting into the alpha and beta lobes are born after puparium formation. Visualization of individual MB neurons has also revealed how different neurons acquire their characteristic axon projections. During the larval stage, axons of all MB neurons bifurcate into both the dorsal and medial lobes. Shortly after puparium formation, larval MB neurons are selectively pruned according to birthdays. Degeneration of axon branches makes early-born gamma neurons retain only their main processes in the peduncle, which then project into the adult gamma lobe without bifurcation. In contrast, the basic axon projections of the later-born (alpha'/beta') larval neurons are preserved during metamorphosis. This study illustrates the cellular organization of mushroom bodies and the development of different MB neurons at the single cell level. It allows for future studies on the molecular mechanisms of mushroom body development.

The Drosophila E74 gene is required for metamorphosis and plays a role in the polytene chromosome puffing response to ecdysone

Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1455-1465 ◽  
Author(s):  
J.C. Fletcher ◽  
K.C. Burtis ◽  
D.S. Hogness ◽  
C.S. Thummel
Keyword(s):  
Gene Expression ◽  
Salivary Gland ◽  
Critical Role ◽  
Polytene Chromosomes ◽  
Transcription Unit ◽  
Loss Of Function ◽  
Phenotypic Analysis ◽  
Pupal Development ◽  
Puparium Formation ◽  
Early Puff

The steroid hormone ecdysone initiates Drosophila metamorphosis by reprogramming gene expression during late larval and prepupal development. The ecdysone-inducible gene E74, a member of the ets proto-oncogene family, has been proposed to play a key role in this process. E74 is encoded within the 74EF early puff and consists of two overlapping transcription units, E74A and E74B. To assess the function(s) of E74 during metamorphosis, we have isolated and characterized recessive loss-of-function mutations specific to each transcription unit. We find that mutations in E74A and E74B are predominantly lethal during prepupal and pupal development, consistent with a critical role for their gene products in metamorphosis. Phenotypic analysis reveals that E74 function is required for both pupariation and pupation, and for the metamorphosis of both larval and imaginal tissues. E74B mutants are defective in puparium formation and head eversion and die as prepupae or cryptocephalic pupae, while E74A mutants pupariate normally and die either as prepupae or pharate adults. We have also investigated the effects of the E74 mutations on gene expression by examining the puffing pattern of the salivary gland polytene chromosomes in newly formed mutant prepupae. Most puffs are only modestly affected by the E74B mutation, whereas a subset of late puffs are sub-maximally induced in E74A mutant prepupae. These observations are consistent with Ashburner's proposal that early puff proteins induce the formation of late puffs, and define E74A as a regulator of late puff activity. They also demonstrate that E74 plays a wide role in reshaping the insect during metamorphosis, affecting tissues other than the salivary gland in which it was originally identified.

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