- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- Sex-biased regulation of body size by nutrient-responsive...
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
Sex-biased regulation of body size by nutrient-responsive signaling pathways in Drosophila Millington, Jason William
Abstract
Sexual size dimorphism (SSD) is common throughout the animal kingdom. In the fruit fly, Drosophila melanogaster, females are ~30% larger than males. Over the past two decades, studies in Drosophila have expanded our knowledge of the genetic and dietary requirements for growth. However, it remains incompletely understood how males and females differ in the regulation of growth. The insulin/insulin-like growth factor signaling pathway (IIS) was found to be a key regulator of nutrient-dependent growth and body size. The appropriate coupling of growth with dietary nutrients is known as body size plasticity. Recent studies have implicated both dietary nutrients and IIS in establishing SSD, but the mechanism remains poorly understood. To better understand how males and females differ in growth, I used Drosophila to perform a series of studies examining the contribution of nutrients and IIS on growth in both sexes. In Chapter 2, I found that IIS activity is required for increased female body size. Further, genetically augmenting IIS in males is sufficient for increased body size. In Chapter 3, I build upon this characterization and identify that in a high protein dietary context, females increase IIS activity and body size more than males. This results in increased female body size plasticity. Specifically, when dietary protein is abundant, females produce high levels of the insulinotropic factor Stunted which promotes increased IIS and larger body size. This mechanism was dependent on the sex determination gene transformer. These findings elucidate a molecular mechanism underlying the sex difference in body size plasticity. In Chapter 4, I present evidence that in a low-sugar dietary context both sexes increase growth via distinct mechanisms to achieve the same phenotype. Specifically, males increase IIS activity whereas females increase target of rapamycin (TOR) signaling to reach a larger body size. Together, my thesis provides novel mechanistic insight into how males and females differ in their phenotypic response to genetic manipulation and dietary manipulation. This work provides the basis for future studies to identify conserved sex differences in the regulation of nutrient-responsive pathways, and ultimately will inform our knowledge of the sex-biased risk of human metabolic disease.
Item Metadata
Title |
Sex-biased regulation of body size by nutrient-responsive signaling pathways in Drosophila
|
Creator | |
Supervisor | |
Publisher |
University of British Columbia
|
Date Issued |
2021
|
Description |
Sexual size dimorphism (SSD) is common throughout the animal kingdom. In
the fruit fly, Drosophila melanogaster, females are ~30% larger than males. Over the
past two decades, studies in Drosophila have expanded our knowledge of the
genetic and dietary requirements for growth. However, it remains incompletely
understood how males and females differ in the regulation of growth. The
insulin/insulin-like growth factor signaling pathway (IIS) was found to be a key
regulator of nutrient-dependent growth and body size. The appropriate coupling of
growth with dietary nutrients is known as body size plasticity. Recent studies have
implicated both dietary nutrients and IIS in establishing SSD, but the mechanism
remains poorly understood. To better understand how males and females differ in
growth, I used Drosophila to perform a series of studies examining the contribution
of nutrients and IIS on growth in both sexes.
In Chapter 2, I found that IIS activity is required for increased female body
size. Further, genetically augmenting IIS in males is sufficient for increased body
size. In Chapter 3, I build upon this characterization and identify that in a high protein
dietary context, females increase IIS activity and body size more than males. This
results in increased female body size plasticity. Specifically, when dietary protein is
abundant, females produce high levels of the insulinotropic factor Stunted which
promotes increased IIS and larger body size. This mechanism was dependent on
the sex determination gene transformer. These findings elucidate a molecular
mechanism underlying the sex difference in body size plasticity. In Chapter 4, I
present evidence that in a low-sugar dietary context both sexes increase growth via
distinct mechanisms to achieve the same phenotype. Specifically, males increase
IIS activity whereas females increase target of rapamycin (TOR) signaling to reach a
larger body size. Together, my thesis provides novel mechanistic insight into how
males and females differ in their phenotypic response to genetic manipulation and
dietary manipulation. This work provides the basis for future studies to identify
conserved sex differences in the regulation of nutrient-responsive pathways, and
ultimately will inform our knowledge of the sex-biased risk of human metabolic
disease.
|
Genre | |
Type | |
Language |
eng
|
Date Available |
2021-08-11
|
Provider |
Vancouver : University of British Columbia Library
|
Rights |
Attribution-NonCommercial-NoDerivatives 4.0 International
|
DOI |
10.14288/1.0401369
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Graduation Date |
2021-11
|
Campus | |
Scholarly Level |
Graduate
|
Rights URI | |
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International