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Developing an eggshell marker based on a dominant female sterile mutation for the identification of complete follicle cell clones in Drosophila melanogasterEleiche, Aliaa Abdel-Salam. January 2006 (has links)
No description available.
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The genetic dissection of the fruitless gene's functions during embryogenesis in Drosophila melanogasterSong, Ho-Juhn 16 August 2001 (has links)
The fruitless (fru) gene in Drosophila melanogaster is a multifunctional
gene having sex-specific functions in the regulation of male sexual behavior and
sex-nonspecific functions affecting adult viability and external morphology. While
much attention has focused on fru's sex-specific roles, little is known about its sex-nonspecific
functions. The embryonic central nervous system (CNS) is a prime
model system in which to study the genetic control of axonal outgrowth and proper
CNS formation. I have examined fru's sex-nonspecific role in embryonic neural
development. fru transcripts and FRU proteins from sex-nonspecific promoters are
expressed beginning at the earliest stages of neurogenesis and subsequently in both
neurons and glia. In embryos that lack most or all fru function, Fasciclin II- and
BP102-positive axons appeared to defasciculate from their normal pathway and
fasciculate along aberrant neuronal pathways, suggesting that one of fru's sex-nonspecific
roles is to regulate axonal differentiation. I next examined whether the
loss of fru function in FRU-expressing neuronal precursors causes neuronal fate
change. Analysis of fru mutant embryos revealed a lack of Even-skipped (Eve)
staining in Eve-expressing neurons, ectopic Eve staining in non-Eve-expressing
neurons and mispositioned dorsal Eve-expressing neurons, which suggests that fru
functions to maintain neuronal identity rather than to specify neuronal fate. In fru
mutants these defects in axonal projections and in Eve staining were rescued by the
expression of specific fru transgenes.
To better understand fru's function in the formation of the embryonic CNS,
I dissected out fru's function in neuron and glia through a genetic interaction study.
fru genetically interacts in neurons with longitudinal lacking to make proper axonal
projections. In addition, fru might be in the same genetic pathway as roundabout
(robo), a repulsive guidance receptor, and commissureless, a downregulator of
Robo, to ensure proper axonal pathfinding. Surprisingly, fru interacts with
tramtrack and glial cells missing to repress neuronal differentiation in the lateral
glia and with single-minded for the development of midline glia. Taken together,
fru function is required for proper axonal pathfinding in neurons and for proper
development of lateral and midline glia. / Graduation date: 2002
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Discovery and characterisation of new miRNAs during embryogenesis of D. melanogasterMa, Hsiu-Ching January 2011 (has links)
No description available.
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Developing an eggshell marker based on a dominant female sterile mutation for the identification of complete follicle cell clones in Drosophila melanogasterEleiche, Aliaa Abdel-Salam. January 2006 (has links)
Patterning of the body axes of the Drosophila embryo depends on maternally expressed genes, some of which function in the follicular epithelium of the developing egg chamber. Many such genes were identified in genetic screens for homozygous mutant females that produce abnormal embryos. However, mutations in zygotically required maternal effect genes are homozygous lethal, and therefore viable females cannot be recovered using this screening approach. This limitation can be overcome by generating homozygous mutant follicle cell clones in heterozygous females using a system that induces site-specific mitotic recombination events. However, to date, eggs produced from egg chambers with complete follicle cell clones cannot be directly identified. We have developed an eggshell marker for follicle cell clones using a dominant negative (DN) allele of the gene defective chorion (dec). Females with a single copy of this allele, decDN, lay collapsed eggs and are therefore sterile. Site-specific mitotic recombination events induced in females heterozygous for decDN and a mutation on the homologous chromosome arm result in homozygous mutant follicle cells that have lost decDN. Therefore, egg chambers with the entire follicular epithelium homozygous mutant generate intact eggs that can be unambiguously identified amongst otherwise collapsed eggs.
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Embryonic development of the olfactory system in Drosophila melanogasterPrieto Godino, Laura Lucía January 2011 (has links)
No description available.
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Investigating pellino function in Drosophila developmentSarac, Amila. January 2007 (has links)
Although many of the genes and pathways involved in Drosophila embryogenesis have been thoroughly investigated, a complete understanding of the mechanisms behind these processes is still lacking. In order to gain a better perspective, the main objective of current research is to identify additional components of the signaling pathways that are crucial for normal Drosophila development. / One such developmental process is germ band retraction, which occurs in mid-embryogenesis and consists of the movement of the tail end of the germ band, or embryo proper, to its final posterior position. One of our primary objectives is to identify the signaling pathways behind this process. To this end, we investigated the 7T2 mutant, which fails to retract. This zygotic lethal mutant was originally uncovered in a screen for maternal-effect U-shaped embryonic phenotypes. Using a combination of meiotic recombination with molecularly mapped P-element insertions and complementation tests with deficiencies, we mapped the 7T2 mutant to the chromosomal region containing the gene pellino. Here, we show that both pellino mRNA and Pellino protein are missing in the 7T2 mutant tissue, indicating that 7T2 is a loss of function allele of pellino. / Further characterization of the 7T2 mutant revealed three distinct phenotypes: germ band retraction defects, twisted germ bands and head defects. Based on these observations, we propose that pellino is involved in several biological processes during early Drosophila development. Here we show that pellino is involved in the JNK pathway through genetic interaction with hemipterous, an upstream member of the JNK pathway. In addition, we provide preliminary evidence suggesting that the expression of Twist, a protein induced by the Toll pathway, is affected in the absence of pellino, suggesting a role for pellino in dorsal-ventral pattern formation.
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Investigating pellino function in Drosophila developmentSarac, Amila. January 2007 (has links)
No description available.
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Follicle cell fate determination in the Drosophila ovary : the role of the capicua geneRounding Atkey, Matthew January 2005 (has links)
The gene capicua is required for the establishment of dorsal-ventral polarity in the Drosophila melanogaster ovary. Loss of capicua function in the follicle cells results in dorsalization of both the embryo and eggshell. The most prominent dorsal features of the Drosophila eggshell are the dorsal appendages. We show that loss of capicua function results in the ventral ectopic specification of dorsal appendage-producing follicle cell fate. This cell fate change is due in part to the ectopic expression of genes such as mirror and Broad-Complex in capicua mutant ovaries. When either mirror or Broad-Complex are ectopically expressed independently of loss of capicua function, they generate a phenotype similar to the capicua mutant phenotype. We propose that Capicua normally acts in the ventral follicle cells to repress the expression of genes that pattern the dorsal follicle cells. EGF receptor signaling may normally inactivate Capicua repression in the dorsal follicle cells.
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The permeability of Drosophila melanogaster embryosWatson, Catherine E. January 1990 (has links)
Drosophila are used extensively for genetic, developmental and now molecular biology research. At present, germline transformation of these organisms can only be achieved by microinjection of P-element vectors into the pole cells of young embryos. The technique of microinjection however, requires a delicate touch and is quite laborious. Therefore, the development of a rapid and simple technique was investigated.
Electroporation, like microinjection, is a physical means of introducing DNA into a cell and is therefore potentially applicable to all cell types. Electroporation involves the use of an electrical current to create pores in the membrane of a cell. Macromolecules, such as DNA may enter a cell via these pores. Electroporation is a quick, reproducible, and efficient method for transforming cells. Through studies of the survival and permeability of Drosophila melanogaster embryos exposed to electrical currents, it was discovered that although the survival of the embryos decreased steadily as field strength increased, the embryos did not become permeable to a water soluble dye unless a pulse of 10 kV/cm was applied. Few embryos survived this extreme voltage required for dye uptake. Attempts to introduce DNA into dechorionated Drosophila embryos utilizing this technique however, produced no transformants. These results suggested that the remaining protective coatings of the dechorionated embryo were obstructing efficient pore formation, thus preventing DNA penetration.
In view of these results, methods to eliminate the wax layer, present between the chorion and vitelline membrane of laid eggs,
were examined. Wax removal by detergent solubilization, solvent extraction and melting by heating were investigated, yet did not produce a satisfactory procedure. / Medicine, Faculty of / Biochemistry and Molecular Biology, Department of / Graduate
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Synthesis and regulation of gurken mRNA in the Drosophila germlineCáceres, Lucía. January 2007 (has links)
No description available.
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