Wingless induces transdetermination in developing Drosophila imaginal discs

Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1263-1272 ◽  
Author(s):  
L. Maves ◽  
G. Schubiger
Keyword(s):  
Molecular Level ◽  
Ectopic Expression ◽  
Imaginal Discs ◽  
Developmental Studies ◽  
New Approach ◽  
Cell Determination ◽  
Disc Cells ◽  
The Subject ◽  
Insight Into

Drosophila imaginal discs, the precursors of the adult fly appendages, have been the subject of intensive developmental studies, particularly on cell determination. Cultured disc fragments are recognized not only for the ability to maintain their determined state through extra cell divisions but also for the ability to transdetermine, or switch to the determined state of a different disc. An understanding of transdetermination at a molecular level will provide further insight into the requirements for maintaining cell determination. We find that ectopic expression of the Drosophila gene wingless induces transdetermination of foreleg imaginal disc cells to wing cells. This transdetermination occurs in foreleg discs of developing larvae without disc fragmentation. The in situ-transdetermining cells localize to the dorsal region of the foreleg disc. This wingless-induced transdetermination event is remarkably similar to the leg-to-wing switch that occurs after leg disc culture. Thus we have identified a new approach to a molecular dissection of transdetermination.

Transcription of the segment-polarity gene wingless in the imaginal discs of Drosophila, and the phenotype of a pupal-lethal wg mutation

Development ◽  
1988 ◽  
Vol 102 (3) ◽  
pp. 489-497 ◽  
Author(s):  
N.E. Baker
Keyword(s):  
In Situ Hybridization ◽  
Imaginal Discs ◽  
Apical Cytoplasm ◽  
Segment Polarity ◽  
Disc Cells ◽  
Segment Polarity Gene ◽  
Drosophila Embryos ◽  
Polarity Gene

Wingless (wg) is a segment-polarity gene in Drosophila which is related to the murine proto-oncogene int1. In Drosophila embryos, wg transcription defines part of each parasegment. In situ hybridization shows that wg is also expressed in the imaginal discs which give rise to the adult during metamorphosis. Transcripts are localized in the apical cytoplasm of disc cells, and accumulate in different patterns in dorsal and ventral discs. The wgCX3 mutation produces morphological defect in the adult structures derived from these imaginal discs. The results show that wg is involved in the development of the adult, as well as the embryo, but that the imaginal discs do not express this segment-polarity gene in an identical pattern to the embryonic segments.

scholarly journals Transvection in the Drosophila Ultrabithorax gene: a Cbx1 mutant allele induces ectopic expression of a normal allele in trans.

Genetics ◽  
1990 ◽  
Vol 126 (1) ◽  
pp. 177-184 ◽  
Author(s):  
J E Castelli-Gair ◽  
J L Micol ◽  
A García-Bellido
Keyword(s):  
Double Mutant ◽  
Ectopic Expression ◽  
Imaginal Discs ◽  
Wing Disc ◽  
Loss Of Function ◽  
Normal Allele ◽  
Single Mutant ◽  
Adult Wing ◽  
Disc Cells ◽  
In Cis

Abstract In wild-type Drosophila melanogaster larvae, the Ultrabithorax (Ubx) gene is expressed in the haltere imaginal discs but not in the majority of cells of the wing imaginal discs. Ectopic expression of the Ubx gene in wing discs can be elicited by the presence of Contrabithorax (Cbx) gain-of-function alleles of the Ubx gene or by loss-of-function mutations in Polycomb (Pc) or in other trans-regulatory genes which behave as repressors of Ubx gene activity. Several Ubx loss-of-function alleles cause the absence of detectable Ubx proteins (UBX) or the presence of truncated UBX lacking the homeodomain. We have compared adult wing phenotypes with larval wing disc UBX patterns in genotypes involving double mutant chromosomes carrying in cis one of those Ubx mutations and the Cbx1 mutation. We show that such double mutant genes are (1) active in the same cells in which the single mutant Cbx1 is expressed, although they are unable to yield functional proteins, and (2) able to induce ectopic expression of a normal homologous Ubx allele in a part of the cells in which the single mutant Cbx1 is active. That induction is conditional upon pairing of the homologous chromosomes (the phenomenon known as transvection), and it is not mediated by UBX. Depletion of Pc gene products by Pc3 mutation strongly enhances the induction phenomenon, as shown by (1) the increase of the number of wing disc cells in which induction of the homologous allele is detectable, and (2) the induction of not only a paired normal allele but also an unpaired one.

Ectopic expression of wingless in imaginal discs interferes with decapentaplegic expression and alters cell determination

Development ◽  
1996 ◽  
Vol 122 (11) ◽  
pp. 3519-3529 ◽  
Author(s):  
L.A. Johnston ◽  
G. Schubiger
Keyword(s):  
Ectopic Expression ◽  
Imaginal Discs ◽  
Dorsal Side ◽  
Homeotic Genes ◽  
Cell Determination ◽  
Segment Polarity ◽  
High Level ◽  
Dorsal Cells ◽  
Dose Dependent ◽  
Dorsal Pattern

We have expressed the segment polarity gene wingless (wg) ectopically in imaginal discs to examine its regulation of both ventral patterning and transdetermination. By experimentally manipulating the amount of Wg protein, we show that different thresholds of Wg activity elicit different outcomes, which are mediated by regulation of decapentaplegic (dpp) expression and result in alterations in the expression of homeotic genes. A high level of Wg activity leads to loss of all dorsal pattern elements and the formation of a complete complement of ventral pattern elements on the dorsal side of legs, and is correlated with repression of dpp expression. wg expression in dorsal cells of each disc also leads to dose-dependent transdetermination in those cells in homologous discs such as the labial, antennal and leg, but not in cells of dorsally located discs. When dpp expression is repressed by high levels of Wg, transdetermination does not occur, confirming that dpp participates with wg to induce transdetermination. These and other experiments suggest that dorsal expression of wg alters disc patterning and disc cell determination by modulating the expression of dpp. The dose-dependent effects of wg on dpp expression, ventralization of dorsal cells and transdetermination support a model in which wg functions as a morphogen in imaginal discs.

In-situ X-ray Studies of Clean Catalytic Technologies

2011 ◽  
Vol 1351 ◽  
Author(s):  
Adam F. Lee ◽  
Christine V. Ellis ◽  
Mark A. Newton ◽  
Christopher M. Parlett ◽  
Karen Wilson
Keyword(s):  
Rational Design ◽  
Heterogeneous Catalysts ◽  
Molecular Level ◽  
Aerobic Oxidation ◽  
Allylic Alcohols ◽  
Time Resolved ◽  
X Ray ◽  
Adsorbed Layers ◽  
Insight Into

ABSTRACTThe rational design of new heterogeneous catalysts for clean chemical technologies can be accelerated by molecular level insight into surface chemical processes. In-situ methodologies, able to provide time-resolved and/or pressure dependent information on the evolution of reacting adsorbed layers over catalytically relevant surfaces, are therefore of especial interest. Here we discuss the application of in-situ XPS and in-situ, synchronous DRIFTS/MS/XAS methodologies to elucidate the active site in Pd-catalyzed, selective aerobic oxidation of allylic alcohols.

Christopher Howard Andrewes, 7 June 1896 - 31 December 1987

1991 ◽  
Vol 37 ◽  
pp. 33-54
Keyword(s):  
Natural History ◽  
Molecular Level ◽  
Research Output ◽  
Medical Sciences ◽  
Left Behind ◽  
The World ◽  
The Subject ◽  
Personal Career ◽  
Organization Of Science ◽  
Insight Into

Christopher Howard Andrewes passed peacefully away on 31 December 1987 at the home of his son. He was a man of great significance in the development of the subject of virology in Britain, and indeed in the world. Furthermore, his life spanned a period of great changes in the organization of science and in the way that research in the medical sciences was conducted. In a way his personal career and his research output reflect the transition from a period when biology was largely a descriptive subject to one when analysis and technology were applied and began to give us an insight into the fundamental processes involved, down to the molecular level. Though he entered with great enthusiasm into this process and the progression of knowledge, he retained to the end his schoolboy love of natural history, and the world of nature as we experience it. He left behind a considerable inheritance of important scientific observations and concepts and also a cohort of individuals whom he had taught or had influenced in other ways to understand or practise science.

scholarly journals Metaproteomics: Much More than Measuring Gene Expression in Microbial Communities

mSystems ◽  
2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Manuel Kleiner
Keyword(s):  
Gene Expression ◽  
Community Structure ◽  
Microbial Community ◽  
Microbial Communities ◽  
Large Scale ◽  
Molecular Level ◽  
Carbon Sources ◽  
Community Members ◽  
Insight Into

ABSTRACT Metaproteomics is the large-scale identification and quantification of proteins from microbial communities and thus provides direct insight into the phenotypes of microorganisms on the molecular level. Initially, metaproteomics was mainly used to assess the “expressed” metabolism and physiology of microbial community members. However, recently developed metaproteomic tools allow quantification of per-species biomass to determine community structure, in situ carbon sources of community members, and the uptake of labeled substrates by community members. In this perspective, I provide a brief overview of the questions that we can currently address, as well as new metaproteomics-based approaches that we and others are developing to address even more questions in the study of microbial communities and plant and animal microbiota. I also highlight some areas and technologies where I anticipate developments and potentially major breakthroughs in the next 5 years and beyond.

Direct Observations of the Epitaxial Growth of Sputtered Ag on Si

1973 ◽  
Vol 31 ◽  
pp. 122-123
Author(s):  
J. S. Maa ◽  
Thos. E. Hutchinson
Keyword(s):  
Epitaxial Growth ◽  
Film Growth ◽  
Ion Beam ◽  
Ion Beam Sputtering ◽  
Microscopy Technique ◽  
Direct Observations ◽  
In Situ Electron Microscopy ◽  
Beam Sputtering ◽  
The Subject

The growth of Ag films deposited on various substrate materials such as MoS2, mica, graphite, and MgO has been investigated extensively using the in situ electron microscopy technique. The three stages of film growth, namely, the nucleation, growth of islands followed by liquid-like coalescence have been observed in both the vacuum vapor deposited and ion beam sputtered thin films. The mechanisms of nucleation and growth of silver films formed by ion beam sputtering on the (111) plane of silicon comprise the subject of this paper. A novel mode of epitaxial growth is observed to that seen previously.The experimental arrangement for the present study is the same as previous experiments, and the preparation procedure for obtaining thin silicon substrate is presented in a separate paper.

Positive Reintegration as a Way of Small and Medium-Sized Business Development

2012 ◽  
pp. 83-88
Author(s):  
A. Zolotov ◽  
M. Mukhanov
Keyword(s):  
Policy Implementation ◽  
Policy Making ◽  
Economic Reforms ◽  
Alternative Possibility ◽  
New Approach ◽  
Compensation Mechanisms ◽  
Policy Making Process ◽  
Monitoring And Enforcement ◽  
The Subject ◽  
Modernization Process

А new approach to policy-making in the field of economic reforms in modernizing countries (on the sample of SME promotion) is the subject of this article. Based on summarizing the ten-year experience of de-bureaucratization policy implementation to reduce the administrative pressure on SME, the conclusion of its insufficient efficiency and sustainability is made. The alternative possibility is the positive reintegration approach, which provides multiparty policy-making process, special compensation mechanisms for the losing sides, monitoring and enforcement operations. In conclusion matching between positive reintegration principles and socio-cultural factors inherent in modernization process is provided.

Social organization in the Orcadian Neolithic: identification of elite domestic structures and settlements through analysis of excavation data

2018 ◽  
Vol 40 (1) ◽  
pp. 25-53 ◽  
Author(s):  
David MacInnes
Keyword(s):  
Social Organization ◽  
Qualitative Data ◽  
Social Hierarchy ◽  
Published Data ◽  
Early Neolithic ◽  
Late Neolithic ◽  
New Approach ◽  
Qualitative Evidence ◽  
Methods Of Analysis ◽  
The Subject

The nature of social organization during the Orcadian Neolithic has been the subject of discussion for several decades with much of the debate focused on answering an insightful question posed by Colin Renfrew in 1979. He asked, how was society organised to construct the larger, innovative monuments of the Orcadian Late Neolithic that were centralised in the western Mainland? There are many possible answers to the question but little evidence pointing to a probable solution, so the discussion has continued for many years. This paper takes a new approach by asking a different question: what can be learned about Orcadian Neolithic social organization from the quantitative and qualitative evidence accumulating from excavated domestic structures and settlements?In an attempt to answer this question, quantitative and qualitative data about domestic structures and about settlements was collected from published reports on 15 Orcadian Neolithic excavated sites. The published data is less extensive than hoped but is sufficient to support a provisional answer: a social hierarchy probably did not develop in the Early Neolithic but almost certainly did in the Late Neolithic, for which the data is more comprehensive.While this is only one approach of several possible ways to consider the question, it is by exploring different methods of analysis and comparing them that an understanding of the Orcadian Neolithic can move forward.

Importance of the Intersection of Library and Information Sciences with Systems Theory

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Hannah Lee
Keyword(s):  
System Theory ◽  
General System ◽  
General System Theory ◽  
Von Bertalanffy ◽  
Meta Level ◽  
Professional Field ◽  
The Subject ◽  
Critical Insight ◽  
Insight Into ◽  
Information Sciences

This paper is the attempt to show how system theory could provide critical insight into the transdisciplinary field of library and information sciences (LIS). It begins with a discussion on the categorization of library and information sciences as an academic and professional field (or rather, the lack of evidence on the subject) and what is exactly meant by system theory, drawing upon the general system theory established by Ludwig von Bertalanffy. The main conversation of this paper focuses on the inadequacies of current meta-level discussions of LIS and the benefits of general system theory (particularly when considering the exponential rapidity in which information travels) with LIS.

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