Abstract: Competition between cells within organisms has been recognized in social amoebae, Drosophila, and the inception and metastasis of cancer. """"""""Winner"""""""" cells exhibit advantages in growth, adhesion or survival, putatively increasing the overall fitness of the individual organism. However, only competition among germ cells results in direct inheritance of """"""""winner"""""""" traits. As gametes are established during early embryonic development from primordial germ cells (PGCs), heritable genetic mutations that undergo selection and drive evolution of species must occur in this cell lineage. I previously demonstrated germline stem cell competition in a basal chordate and recent work hints at a parallel phenomenon in mammals. Our goal is to determine the gene regulatory and genetic bases for germ cell competition in mice. We will study competition among PGCs in the mouse embryo in three aspects of their development: the allocation of pluripotent epiblast cells to the germline, the migration of PGCs to the gonadal ridges, and the expansion of PGCs in the embryonic gonad as they commence sex-specific differentiation. To model in vivo competition among isogenic PGCs, we will employ genetic marking strategies;comparison of """"""""winning"""""""" PGC clones to unpurified or non-dominant ones will reveal gene expression and epigenetic differences that potentially bestow an advantage to developing germ cells. To model competitive advantage by genetic alteration, we will employ 7 different PGC mutants that we previously identified in a forward genetic screen of mouse embryos. We will use transplantation approaches to pit these PGC depletion, overabundance and migration phenotypes against one another in vivo and ask how a particular genetic mutation impacts fitness to enter the germline, migrate, and contribute to gamete biogenesis. We hope to gain a molecular understanding of how PGCs interact with their niches and provide insight into basic regulatory and genetic mechanisms of cellular selection that underlie evolution and tumorogenesis. Public Health Relevance: Since the origin and progression of cancer occurs by cells gaining a selective advantage in survival, proliferation or migration, study of the mechanism of cell competition will identify genetic alterations, regulatory or epigenetic changes that become dysregulated in tumor development and could be useful in cancer diagnosis or targeted for therapy. In assisted reproductive technologies, where the prospect of differentiating gametes from pluripotent stem cells looms on the horizon, understanding germ cell competition will be instrumental to informing the potential risks and biological consequences of short circuiting in vivo germ cell development.

Agency
National Institute of Health (NIH)
Institute
Office of The Director, National Institutes of Health (OD)
Type
NIH Director’s New Innovator Awards (DP2)
Project #
3DP2OD007420-01S1
Application #
8731294
Study Section
Program Officer
Basavappa, Ravi
Project Start
2010-09-30
Project End
2015-06-30
Budget Start
2010-09-30
Budget End
2015-06-30
Support Year
1
Fiscal Year
2014
Total Cost
$51,919
Indirect Cost
$18,955
Name
University of California San Francisco
Department
Obstetrics & Gynecology
Type
Schools of Medicine
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94143
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Sousa Martins, Joao P; Liu, Xueqing; Oke, Ashwini et al. (2016) DAZL and CPEB1 regulate mRNA translation synergistically during oocyte maturation. J Cell Sci 129:1271-82
Arora, Ripla; Fries, Adam; Oelerich, Karina et al. (2016) Insights from imaging the implanting embryo and the uterine environment in three-dimensions. Development :
Tran, Nam D; Kissner, Michael; Subramanyam, Deepa et al. (2016) A miR-372/let-7 Axis Regulates Human Germ Versus Somatic Cell Fates. Stem Cells 34:1985-91
Arora, Ripla; Abby, Emilie; Ross, Adam D J et al. (2016) Meiotic onset is reliant on spatial distribution but independent of germ cell number in the mouse ovary. J Cell Sci 129:2493-9
Cantú, Andrea V; Altshuler-Keylin, Svetlana; Laird, Diana J (2016) Discrete somatic niches coordinate proliferation and migration of primordial germ cells via Wnt signaling. J Cell Biol 214:215-29
Faire, Mehlika; Skillern, Amanda; Arora, Ripla et al. (2015) Follicle dynamics and global organization in the intact mouse ovary. Dev Biol 403:69-79
Arora, Ripla; Altman, Eran; Tran, Nam D et al. (2014) Novel domains of expression for orphan receptor tyrosine kinase Ror2 in the human and mouse reproductive system. Dev Dyn 243:1037-45
Chen, Li; Faire, Mehlika; Kissner, Michael D et al. (2013) Primordial germ cells and gastrointestinal stromal tumors respond distinctly to a cKit overactivating allele. Hum Mol Genet 22:313-27

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