The Small GTPase Rheb Is Required for Spermatogenesis but not Oogenesis
type: CreativeWork
description: The process of germ cell development is under the tight control of various signaling pathways among which the PI3K-PKB-mTOR pathway is of critical importance. Previous studies have demonstrated sex-specific roles for several components of this pathway. In the current study I aimed to evaluate the role of Rheb, a member of the small GTPase superfamily and a critical component for mTORC1 activation, in male and female gametogenesis. The function of Rheb in development and the nervous system has been extensively studied, but little was known about its role in the germline. I have exploited genetic approaches in the mouse to study the role of Rheb in the germline and have identified an essential role in spermatogenesis. Conditional knockout (cKO) of Rheb in the male germline resulted in severe oligoasthenoteratozoospermia and male sterility. More detailed phenotypic analyses uncovered an age-dependent meiotic progression defect combined with subsequent abnormalities in spermiogenesis as evidenced by abnormal sperm morphology. In the female, however, germ-cell specific inactivation of Rheb was not associated with any discernible abnormality; these cKO mice were fertile with morphologically unremarkable ovaries, normal primordial follicle formation, and subsequent follicle maturation. The absence of an abnormal ovarian phenotype is striking given previous studies demonstrating a critical role for the mTORC1 pathway in the maintenance of primordial follicle pool. In conclusion, our findings demonstrate an essential role of Rheb in diverse aspects of spermatogenesis but suggest the existence of functionally-redundant factors that can compensate for Rheb deficiency within oocytes.
abstract: The process of germ cell development is under the tight control of various signaling pathways among which the PI3K-PKB-mTOR pathway is of critical importance. Previous studies have demonstrated sex-specific roles for several components of this pathway. In the current study I aimed to evaluate the role of Rheb, a member of the small GTPase superfamily and a critical component for mTORC1 activation, in male and female gametogenesis. The function of Rheb in development and the nervous system has been extensively studied, but little was known about its role in the germline. I have exploited genetic approaches in the mouse to study the role of Rheb in the germline and have identified an essential role in spermatogenesis. Conditional knockout (cKO) of Rheb in the male germline resulted in severe oligoasthenoteratozoospermia and male sterility. More detailed phenotypic analyses uncovered an age-dependent meiotic progression defect combined with subsequent abnormalities in spermiogenesis as evidenced by abnormal sperm morphology. In the female, however, germ-cell specific inactivation of Rheb was not associated with any discernible abnormality; these cKO mice were fertile with morphologically unremarkable ovaries, normal primordial follicle formation, and subsequent follicle maturation. The absence of an abnormal ovarian phenotype is striking given previous studies demonstrating a critical role for the mTORC1 pathway in the maintenance of primordial follicle pool. In conclusion, our findings demonstrate an essential role of Rheb in diverse aspects of spermatogenesis but suggest the existence of functionally-redundant factors that can compensate for Rheb deficiency within oocytes.
author: Baker, Michael David
language: en
keywords: Monomeric GTP-Binding Proteins, Neuropeptides, Oogenesis, Spermatogenesis
date published: 2016-01-05T19:14:14Z
date modified: 2026-07-24T05:52:26Z
provider: University of Texas Southwestern Medical Center
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Texas Southwestern Medical Center

PropertyValue
property ID: Handle
value: https://hdl.handle.net/2152.5/2712