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106
RNAi interference (RNAi) is a mechanism that knocks down gene expression in variety
of organisms (Nishikura 2001). When a long dsRNA is introduced into the organism, its
double-stranded structure is recognized by a ribonuclease III enzyme named Dicer,
which subsequently cleaves it into smaller fragments named small interfering RNAs
(siRNA). In turn, siRNA directs the cleavage of homologous messenger RNA after
siRNA is incorporated into the RNA-induced silencing complex (RISC) (Nishikura
2001; Hannon 2002). The cleavage of messenger RNA then results in a substantial
decrease in expression of that gene in the organism.
Since its discovery a decade ago, RNAi has become an important and powerful research
tool to investigate gene function in an array of organisms, both in vivo and in vitro. At
the same time, RNAi has also been considered as an promising candidate tool in a
therapeutic research environment for the treatment of diseases (Kim and Rossi 2008).
Recently, researchers developed a large scale RNAi injection method for Drosophila
embryos to identify and characterize the molecular functions of the 14,000 Drosophila
genes (Cornell, Fisher et al. 2008). For molecular biology and genetics research, clinical
and therapeutic applications, RNAi is becoming an indispensable tool for the
advancement of academic and commercial research.
It has been a long time since the first scientist injected DNA into a developing
Drosophila embryo, trying to create a Drosophila strain bearing his gene of interest.
(Rubin and Spradling 1982) More recently, scientists have been injecting dsRNAs into
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 116 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 106 RNAi interference (RNAi) is a mechanism that knocks down gene expression in variety of organisms (Nishikura 2001). When a long dsRNA is introduced into the organism, its double-stranded structure is recognized by a ribonuclease III enzyme named Dicer, which subsequently cleaves it into smaller fragments named small interfering RNAs (siRNA). In turn, siRNA directs the cleavage of homologous messenger RNA after siRNA is incorporated into the RNA-induced silencing complex (RISC) (Nishikura 2001; Hannon 2002). The cleavage of messenger RNA then results in a substantial decrease in expression of that gene in the organism. Since its discovery a decade ago, RNAi has become an important and powerful research tool to investigate gene function in an array of organisms, both in vivo and in vitro. At the same time, RNAi has also been considered as an promising candidate tool in a therapeutic research environment for the treatment of diseases (Kim and Rossi 2008). Recently, researchers developed a large scale RNAi injection method for Drosophila embryos to identify and characterize the molecular functions of the 14,000 Drosophila genes (Cornell, Fisher et al. 2008). For molecular biology and genetics research, clinical and therapeutic applications, RNAi is becoming an indispensable tool for the advancement of academic and commercial research. It has been a long time since the first scientist injected DNA into a developing Drosophila embryo, trying to create a Drosophila strain bearing his gene of interest. (Rubin and Spradling 1982) More recently, scientists have been injecting dsRNAs into |
