{"id":{"repo_id":"utswmed","oai_identifier":"oai:utswmed-ir.tdl.org:2152.5/2712"},"canonical_url":"https://search.dev.ndltd.org/etd/utswmed/oai:utswmed-ir.tdl.org:2152.5/2712","repository":{"repo_id":"utswmed","name":"University of Texas Southwestern Medical Center","base_url":"https://utswmed-ir.tdl.org/server/oai/request"},"display":{"title":"The Small GTPase Rheb Is Required for Spermatogenesis but not Oogenesis","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.","abstract_html":"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_has_math":false,"creators":["Baker, Michael David"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Lum, Lawrence","Castrillon, Diego H.","Brekken, Rolf A.","Amatruda, James F."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016-01-05T19:14:14Z","date_published":"2016-01-05T19:14:14Z","updated_at":"2026-07-24T05:52:26Z","subjects":["Monomeric GTP-Binding Proteins","Neuropeptides","Oogenesis","Spermatogenesis"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["933743736"],"render_values":[{"text":"933743736","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/2152.5/2712","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Lum, Lawrence","Castrillon, Diego H.","Brekken, Rolf A.","Amatruda, James F."]},{"key":"dc:creator","label":"Author","values":["Baker, Michael David"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2016-01-05T19:14:14Z","2013-12","2013-10-01","December 2013","2016-01-05T19:07:55Z"]},{"key":"dc:type","label":"Dc Type","values":["Thesis","text"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Monomeric GTP-Binding Proteins","Neuropeptides","Oogenesis","Spermatogenesis"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2152.5/2712","933743736"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["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."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["The Small GTPase Rheb Is Required for Spermatogenesis but not Oogenesis"]}]}],"canonical_facts":{"dc:contributor":["Lum, Lawrence","Castrillon, Diego H.","Brekken, Rolf A.","Amatruda, James F."],"dc:creator":["Baker, Michael David"],"dc:date":["2016-01-05T19:14:14Z","2013-12","2013-10-01","December 2013","2016-01-05T19:07:55Z"],"dc: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."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2152.5/2712","933743736"],"dc:language":["en"],"dc:subject":["Monomeric GTP-Binding Proteins","Neuropeptides","Oogenesis","Spermatogenesis"],"dc:title":["The Small GTPase Rheb Is Required for Spermatogenesis but not Oogenesis"],"dc:type":["Thesis","text"]},"updated_at":"2026-07-24T05:52:26Z"}