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124
(Dzitoyeva, Dimitrijevic et al. 2001). However, reports from other research groups
showing success with this approach have been rare. My own RNAi injection experiment
did not achieve the expected result. And it could be due to a few reasons. The first
explanation is the lack of chemically-modified RNA oligos. The more plausible
explanation, however, is a limited permeating capability of siRNA oligos through ovary
membrane and ovarioles sheath cells. The siRNA injection approach may require more
precise mastery of injection techniques than embryo injection, too. With all the above
obstacles removed, RNAi by abdominal injection could be full of potential for anyone
who would like to perform RNAi on adult flies with a quick and easy approach.
In sum, Drosophila melanogaster was a great model organism for molecular biology and
genetics research. I screened about 8,000 mutants to obtain two most interesting genes.
Magu and Hebe gene extend lifespan when over-expressed. magu has orthologs across
many species, which gives us some insights about its potential functions in oogenesis,
male spermatogenesis, and blood vessel formation. The Drosophila stem cell driver
strain that Daniel Ford and I characterized will be a useful tool for expressing a gene of
interest in the Drosophila gut. RNAi triggered by intra-abdominal injection technique is
still under development. There are a few roadblocks that need to be removed before any
widespread application of this technique. As an indispensable research tool, Drosophila
will remain probably the favorite model organism for molecular biologists and
geneticists.
Object Description
| Title | Characterization of Drosophila longevity and fecundity regulating genes |
| Author | Li, Yishi |
| Author email | yishili@usc.edu; yishili@gmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Molecular & Computational Biology |
| School | College of Letters, Arts and Sciences |
| Date defended/completed | 2008-08-19 |
| Date submitted | 2008 |
| Restricted until | Unrestricted |
| Date published | 2008-10-31 |
| Advisor (committee chair) | Tower, John |
| Advisor (committee member) |
Finkel, Steven E. Aparicio, Oscar Martin Longo, Valter D Comai, Lucio |
| Abstract | The regulation of Drosophila melanogaster longevity and fecundity involves many factors. Longevity is governed by oxidative stress, stem cell loss, dietary restriction, the insulin/IGF-1 pathway, and other factors. Fecundity is also regulated by multiple tissues and factors, including the germline stem cells and stem cell niche, the fat body, yolk proteins, and sex peptides. The fecundity of wild type female Drosophila gradually declines during aging, suggesting a common pathway regulating longevity and fecundity machinery. Since both mechanisms involve multiple factors, sorting through the Gordian’s knot is a formidable task. Using a PdL mutagenesis approach, I screened for a specific phenotype in thousands of independent mutant strains to examine both regulatory networks simultaneously. Two novel genes, magu and hebe, were identified and characterized to regulate longevity and fecundity. While Drosophila lifespan was extended upon the induction of these genes, fecundity increase requires that the gene induction be in an ideal range to show the expected phenotypic change. I also performed several other projects, including studying the lifespan extension effect of dIAP2, characterization of a Drosophila gut driver strain, and intra-abdominal RNAi injection in adult Drosophila. These projects provided us insight on longevity, fecundity, anti-apoptosis, stem cell biology, RNAi and other aspects of Drosophila research. In sum, Drosophila melanogaster, as a model organism for molecular biology and genetics study, will continue to contribute to the scientific community. |
| Keyword | Drosophila; longevity; fecundity |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m1735 |
| Contributing entity | University of Southern California |
| Rights | Li, Yishi |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@lib.usc.edu |
| Filename | etd-Li-2382 |
| Archival file | uscthesesreloadpub_Volume44/etd-Li-2382.pdf |
Description
| Title | Page 134 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 124 (Dzitoyeva, Dimitrijevic et al. 2001). However, reports from other research groups showing success with this approach have been rare. My own RNAi injection experiment did not achieve the expected result. And it could be due to a few reasons. The first explanation is the lack of chemically-modified RNA oligos. The more plausible explanation, however, is a limited permeating capability of siRNA oligos through ovary membrane and ovarioles sheath cells. The siRNA injection approach may require more precise mastery of injection techniques than embryo injection, too. With all the above obstacles removed, RNAi by abdominal injection could be full of potential for anyone who would like to perform RNAi on adult flies with a quick and easy approach. In sum, Drosophila melanogaster was a great model organism for molecular biology and genetics research. I screened about 8,000 mutants to obtain two most interesting genes. Magu and Hebe gene extend lifespan when over-expressed. magu has orthologs across many species, which gives us some insights about its potential functions in oogenesis, male spermatogenesis, and blood vessel formation. The Drosophila stem cell driver strain that Daniel Ford and I characterized will be a useful tool for expressing a gene of interest in the Drosophila gut. RNAi triggered by intra-abdominal injection technique is still under development. There are a few roadblocks that need to be removed before any widespread application of this technique. As an indispensable research tool, Drosophila will remain probably the favorite model organism for molecular biologists and geneticists. |
