The long-term goal of this project is to elucidate mechanisms of gamete development using Drosophila oogenesis as a model system, and the powerful tools available for genetic and cell biological approaches in Drosophila. A significant health concern is the survival of germline cells in adults exposed to environmental stresses such as poor nutrition and exposure to aggressive pharmaceuticals. Research carried out in this project will impact understanding of protective mechanisms used by immature gametes to ensure their survival through harsh conditions. This project will also investigate a fundamental and conserved aspect of gamete development - some or all of animal gametogenesis occurs in syncytial clusters of cells connected by intercellular bridges called ring canals. Mechanisms modulating intercellular movement of cytoplasm through germline ring canals in response to nutrient availability will be examined. Ring canals are also present between somatic follicle cells of the Drosophila egg chamber, although their function is not known. This project will investigate movement of cytoplasmic components through somatic ring canals, and use novel approaches for disrupting somatic ring canals to determine their function. This information will impact understanding of intercellular movement through small ring canals similar to those connecting developing spermatocytes. In addition, tools developed in this research will be useful for examining somatic ring canals in other Drosophila tissues.
Aim 1 will use genetic approaches to determine the mechanism of the starvation response in oocyte development, by manipulating components of the Drosophila Insulin/insulin-like (IIS)/Tor pathway. Previtellogenic egg chambers mount a response to poor nutrition that includes enlarged P bodies and reorganization of the microtubules. Multiple components of the IIS/Tor pathway will be expressed or knocked down, individually or in combinations, in either the germline or the follicle cell tissues to characterize the consequences in starved egg chambers. New approaches will allow tracking of egg chambers that have been starved to examine their recovery in detail, and mutants affecting P body assembly will be used determine the consequences of crippling the starvation response.
Aim 2 will use new cell marking techniques and fluorescent proteins to illuminate the function of ring canals in the follicle cell epithelium that surrounds the egg chamber. Experiments will determine whether ring canals serve to equilibrate protein levels between transcriptionally uncoordinated cells. New methods for targeted disruption of somatic ring canals will allow phenotypic analysis of disrupted syncytia, which have been elusive. The importance of the role that follicle cell syncytia play during egg chamber development will be better defined following these studies, and these new methods can then be applied to other somatic syncytia involved in development in Drosophila.

Public Health Relevance

Eggs and sperm are the ultimate stem cells, providing the starting point for entire adult animals. This project will study fundamental aspects of egg development using the fruit fly Drosophila melanogaster as a model system and the powerful experimental tools available in flies. The research will help our understanding of how immature eggs protect themselves during periods of poor nutrition.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM043301-24
Application #
8657446
Study Section
Development - 1 Study Section (DEV1)
Program Officer
Nie, Zhongzhen
Project Start
1990-07-01
Project End
2016-04-30
Budget Start
2014-05-01
Budget End
2015-04-30
Support Year
24
Fiscal Year
2014
Total Cost
$616,177
Indirect Cost
$246,101
Name
Yale University
Department
Genetics
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
Burn, K Mahala; Shimada, Yuko; Ayers, Kathleen et al. (2015) Somatic insulin signaling regulates a germline starvation response in Drosophila egg chambers. Dev Biol 398:206-17
Hudson, Andrew M; Cooley, Lynn (2014) Methods for studying oogenesis. Methods 68:207-17
Yan, Dong; Neumüller, Ralph A; Buckner, Michael et al. (2014) A regulatory network of Drosophila germline stem cell self-renewal. Dev Cell 28:459-73
McLean, Peter F; Cooley, Lynn (2014) Bridging the divide: illuminating the path of intercellular exchange through ring canals. Fly (Austin) 8:13-8
McLean, Peter F; Cooley, Lynn (2013) Protein equilibration through somatic ring canals in Drosophila. Science 340:1445-7
Neelakanta, Girish; Hudson, Andrew M; Sultana, Hameeda et al. (2012) Expression of Ixodes scapularis antifreeze glycoprotein enhances cold tolerance in Drosophila melanogaster. PLoS One 7:e33447
Airoldi, Stephanie J; McLean, Peter F; Shimada, Yuko et al. (2011) Intercellular protein movement in syncytial Drosophila follicle cells. J Cell Sci 124:4077-86
Shimada, Yuko; Burn, K Mahala; Niwa, Ryusuke et al. (2011) Reversible response of protein localization and microtubule organization to nutrient stress during Drosophila early oogenesis. Dev Biol 355:250-62
Hudson, Andrew M; Petrella, Lisa N; Tanaka, Akemi J et al. (2008) Mononuclear muscle cells in Drosophila ovaries revealed by GFP protein traps. Dev Biol 314:329-40
Lee, Sangil; Cooley, Lynn (2007) Jagunal is required for reorganizing the endoplasmic reticulum during Drosophila oogenesis. J Cell Biol 176:941-52

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