title: p53 prevents maturation of T cell development to the immature CD4-CD8+ stage in Bcl11b-/- mice.
abstract: Signaling pathways such as the pre-TCR and Wnt pathways regulate alpha/beta T cell differentiation in thymus. Mice lacking an essential component of the pre-TCR exhibit arrest at the (CD4(-)CD8(-)) (CD44(-)CD25(+)) stage (DN3) of thymocyte development, and introduction of p53 deficiency into those mice abrogates this arrest, resulting in transition to the (CD4(+)CD8(+)) double-positive (DP) stage. This paper examines the effect of inactivation of p53 on thymocyte development in Bcl11b(-/-) mice that exhibit arrest at the DN3 or (CD4(-)CD8(+)) immature single-positive (ISP) stage. No DP thymocytes were detected in thymocytes of adoptive transfer experiments in scid mice that were derived from p53(-/-)Bcl11b(-/-) precursors but ISP thymocytes increased in the proportion and in the cell number approximately three times higher than those from Bcl11b(-/-) precursors. Consistently, the level of apoptosis decreased to the level of wild-type precursors. These results suggest that inactivation of p53 is sufficient for DN3 thymocytes to differentiate into the ISP, but not to DP, stage of thymocyte development in Bcl11b(-/-) mice. This provides evidence for a novel p53-mediated checkpoint that regulates the transition from the DN3 to ISP stage of thymocyte development.
authors.affiliation: Department of Molecular Genetics, Graduate School of Medical and Dental Sciences, Niigata University, Asahimachi 1-757, Niigata 951-8122, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Okazuka
authors.forename: Y
authors.initials: Y
authors.lastname: Wakabayashi
authors.forename: M
authors.initials: M
authors.lastname: Kashihara
authors.forename: J
authors.initials: J
authors.lastname: Inoue
authors.forename: T
authors.initials: T
authors.lastname: Sato
authors.forename: M
authors.initials: M
authors.lastname: Yokoyama
authors.forename: S
authors.initials: S
authors.lastname: Aizawa
authors.forename: Y
authors.initials: Y
authors.lastname: Aizawa
authors.forename: Y
authors.initials: Y
authors.lastname: Mishima
authors.forename: R
authors.initials: R
authors.lastname: Kominami
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D016516:CD4-CD8 Ratio / Q000379:methods; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D051379:Mice; D008807:Mice, Inbred BALB C; D013601:T-Lymphocytes / Q000166:cytology* / Q000502:physiology*; D013950:Thymus Gland / Q000166:cytology* / Q000502:physiology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D016159:Tumor Suppressor Protein p53