![Figure 1. Loss of p57 in T cells results in a differentiation block at the DN3-DN4 transition and reduced thymic cellularity. (A) Reverse transcription (RT) and real-time PCR analysis of p57 mRNA in DN3 thymocytes from Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. Normalized data are expressed relative to the value for control mice and are means ± SD for 3 mice. ***P < .005. (B) Gross appearance of the thymus of Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. Scale bar, 2 mm. (C) Total number of thymocytes for individual Lck-Cre/p57[+]/+ (n = 7) and Lck-Cre/p57[+]/F (n = 5) mice at 8 weeks of age. Bars indicate mean values. ***P < .005. (D) Gross appearance of the spleen of Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. Scale bar, 2 mm. (E) Number of TCRβ-positive cells among splenocytes of individual Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age (n = 4). *P < .05. (F-G) Representative flow cytometric analysis of CD4 vs CD8 on thymocytes (F) and of CD44 vs CD25 on electronically gated lineage-negative DN thymocytes (G) from Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. Percentages of each fraction are indicated. (H) Absolute cell number for thymocyte subsets determined by flow cytometry (n = 6 for Lck-Cre/p57[+]/+ and n = 5 for Lck-Cre/p57[+]/F mice). *P < .05, ***P < .005. (I) PCR analysis of genomic DNA for Dβ-to-Jβ rearrangement or V(D)Jβ recombination in DN3 cells from Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. Amplification of a GAPDH gene fragment was performed as an input control. (J) Representative histograms for flow cytometric analysis of intracellular TCRβ expression in DN3 and DN4 thymocytes from Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. (K) Determination of the proportion of cells positive for intracellular TCRβ expression as in panel J. Data are means ± SD for 4 mice. ***P < .005; NS, not significant. (L) RT and real-time PCR analysis of pTα mRNA in DN3 thymocytes from Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. Normalized data are expressed relative to the value for control mice and are means ± SD for 3 mice. ***P < .005.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/123/22/10.1182_blood-2013-10-532390/4/3429f1.jpeg?Expires=1735552462&Signature=tQWEPckMOsIrbwqJow3Bb9I1~FXDwRhymyE8MrJq9-li3PVl6qMgcoLADTop4kQnIq0PCCz52JpY50LgGjE~g2ldNdityPQQ6~8OxdZEfu52bwH~iYKpzGCF34lDokI2kav-~XuJPJmTaxt8G3HbnA9-yJFprt5NZ6n9Fzk0spvoFaxxZSfT2r7WX4glVGXmovRPj53YAt5eflcy-yUqU5xL~kqCssn3qPQ~oHhAjFjijgwqGF8agc8CG2rRieoQmDdKAliir9qxKVUPRFoYJRR-DlX2Ibu2c89KDZar9SBKEMcZeN9tQwGMp-X7oETXs0S3CNovS7KfqBM9fpLjrA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Loss of p57 in T cells results in a differentiation block at the DN3-DN4 transition and reduced thymic cellularity. (A) Reverse transcription (RT) and real-time PCR analysis of p57 mRNA in DN3 thymocytes from Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. Normalized data are expressed relative to the value for control mice and are means ± SD for 3 mice. ***P < .005. (B) Gross appearance of the thymus of Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. Scale bar, 2 mm. (C) Total number of thymocytes for individual Lck-Cre/p57[+]/+ (n = 7) and Lck-Cre/p57[+]/F (n = 5) mice at 8 weeks of age. Bars indicate mean values. ***P < .005. (D) Gross appearance of the spleen of Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. Scale bar, 2 mm. (E) Number of TCRβ-positive cells among splenocytes of individual Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age (n = 4). *P < .05. (F-G) Representative flow cytometric analysis of CD4 vs CD8 on thymocytes (F) and of CD44 vs CD25 on electronically gated lineage-negative DN thymocytes (G) from Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. Percentages of each fraction are indicated. (H) Absolute cell number for thymocyte subsets determined by flow cytometry (n = 6 for Lck-Cre/p57[+]/+ and n = 5 for Lck-Cre/p57[+]/F mice). *P < .05, ***P < .005. (I) PCR analysis of genomic DNA for Dβ-to-Jβ rearrangement or V(D)Jβ recombination in DN3 cells from Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. Amplification of a GAPDH gene fragment was performed as an input control. (J) Representative histograms for flow cytometric analysis of intracellular TCRβ expression in DN3 and DN4 thymocytes from Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. (K) Determination of the proportion of cells positive for intracellular TCRβ expression as in panel J. Data are means ± SD for 4 mice. ***P < .005; NS, not significant. (L) RT and real-time PCR analysis of pTα mRNA in DN3 thymocytes from Lck-Cre/p57[+]/+ and Lck-Cre/p57[+]/F mice at 8 weeks of age. Normalized data are expressed relative to the value for control mice and are means ± SD for 3 mice. ***P < .005.
