Telomerase expression in the germline cycle
Abstract/Contents
- Abstract
- Telomerase inactivation causes loss of the male germline in worms, fish and mice, indicating a conserved dependence on telomere maintenance in this cell lineage. Here, using telomerase reverse transcriptase (Tert) reporter mice, we find that very high telomerase expression is a hallmark of the germline. Telomerase levels in undifferentiated spermatogonia and embryonic stem cells are comparable, and much greater than in somatic progenitor compartments. Within the adult male germline, we uncover an unanticipated gradient of telomerase activity that enables isolation of subpopulation of undifferentiated spermatogonia, the mitotic population where germline stem cells reside, and more mature populations. We exploit this gradient for robust isolation of pure, phenotypically defined subpopulation with the goal of transcriptional and functional analysis. RNA-Seq shows subpopulations of undifferentiated spermatogonia (GFRα1+ and GFRα1- cells) differ principally in receptor tyrosine kinase signaling and cell cycle. We also identify cell surface molecule Melanoma Cell Adhesion Molecule (MCAM) as differentially expressed in these populations. Antibodies to MCAM allow robust isolation of highly enriched populations of GFRα1+ and GFRα1- spermatogonia from adult, wild-type mice without the need to rely on reporter mouse strains. Transplantation into sterile recipients, a proven assay for stem cell activity, shows that both populations demonstrate high transplantation activity and that no germline stem cell activity is found outside the TERTHigh KIT- population. Together, these data provide support for a model for a stem cell pool in which the GFRα1+ and GFRα1- cells make up a heterogeneous stem cell pool and interconvert between these two states based, in part, on access to niche factors. In addition to undifferentiated spermatogonia in adult, the germline expresses high telomerase levels through development and in mature oocytes. We show that primordial germ cells arise from cells expressing high TERT. As development progresses, TERT levels are downregulated with lineage commitment in the soma but remain high in the germline. This pattern to Tert expression is very similar to what is seen for Oct4, an established pluripotency and germline marker.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2017 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Garbuzov, Alina |
|---|---|
| Associated with | Stanford University, Department of Genetics. |
| Primary advisor | Artandi, Steven E |
| Thesis advisor | Artandi, Steven E |
| Thesis advisor | Brunet, Anne, 1972- |
| Thesis advisor | Sage, Julien |
| Thesis advisor | Winslow, Monte |
| Advisor | Brunet, Anne, 1972- |
| Advisor | Sage, Julien |
| Advisor | Winslow, Monte |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Alina Garbuzov. |
|---|---|
| Note | Submitted to the Department of Genetics. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2017. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2017 by Alina Garbuzov
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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