![Figure 1. Thymic growth and increased T cells in Mx1-Cre p107-Single mice (Mx1-Cre Rblox/lox; p130lox/lox; p107+/−). (A, left) Representative control (Ctrl; top) and mutant (Mut; bottom) thymi (dashed lines). (right) H&E staining of representative control (top) and mutant (bottom) thymi. (B) Thymic cellularity (×107, log2 scale) of control and Mx1-Cre p107-Single mice after inactivation of the Rb family in young mice (n = 3 for each time point; asterisks indicate P < 0.05; ns indicates no significant difference; p-values: 3 wk = 0.35, 3 mo = 0.018, 5 mo = 0.04, and 7 mo = 0.03). Horizontal bars indicate the mean. (C) Comparison of thymic cellularity between control and Mx1-Cre Rb/p130 mutant mice at 3 wk (Ctrl: 29 ± 9.5 × 108 cells; Mx1-Cre Rb/p130: 38 ± 24.6 × 108 cells; P = 0.59; n = 3) and 16 wk (Ctrl: 7.6 ± 1.4 × 108 cells; Mx1-Cre Rb/p130: 10.8 ± 7.4 × 108 cells; P = 0.49; n = 3). (D) Oil Red O staining (red) on sections from 2-wk-old control (left), 9-mo-old control (middle), and 9-mo-old Mx1-Cre p107-Single mutant (right) thymi (performed on three mice each). Bars: (A) 200 µm; (D) 100 µm. (E) Quantification of intrathymic T cell progenitor populations between control and mutant mice (n = 3). Lineage-negative populations include CD25− cKit− (Ctrl: 48.65 ± 8.27%; Mut: 42.07 ± 12.95%; P = 0.54), CD25+ cKit− (Ctrl: 44.75 ± 2.90%; Mut: 53.37 ± 11.49%; P = 0.42), CD25− cKit+ (Ctrl: 3.08 ± 3.7%; Mut: 1.65 ± 1.64%; P = 0.45), and CD25+ cKit+ (Ctrl: 3.28 ± 1.28%; Mut: 2.65 ± 0.69%; P = 0.60). (F) Quantification of DN (Ctrl: 22.60 ± 0.82%; Mut: 17.33 ± 4.43%; P = 0.08), DP (Ctrl: 59.73 ± 3.98%; Mut: 73.61 ± 5.43%; P = 0.004), CD4+ T cell (Ctrl: 8.67 ± 0.83%; Mut: 5.00 ± 2.51%; P = 0.04), and CD8+ T cell populations (Ctrl: 8.93 ± 2.96%; Mut: 4.98 ± 1.91%; P = 0.03). (G) T cell BrdU incorporation 1 h after injection was quantified by FACS analysis (n = 3; p-values: Total = 0.002, DN = 0.14, DP = 0.05, CD4+ = 0.24, and CD8+ = 0.22). (H) Quantification of splenic naive T cells in mutants and control mice (n = 3 each; CD4+: Ctrl, 42.76 ± 5.81%; Mut, 55.06 ± 5.42% [P = 0.05]; CD8+: Ctrl, 50.14 ± 5.32%; Mut, 66.24 ± 3.64% [P = 0.03]). All error bars indicate standard error.](https://cdn.rupress.org/rup/content_public/journal/jem/210/6/10.1084_jem.20121716/5/jem_20121716_fig1.jpeg?Expires=1768245119&Signature=ErTWssGSA0FV2tF4b~jNhiHHGC-fi3Wb27-A-pbDMgKCSfLO-iXCyUvdL11sNJul1SErwKqDXdctVJFSrZ4TvC2Yi7QRpoCdOmUYHRdL~TKU1LMYnLFaW17z8lx6RrYOx8nX5yqt1FC5KZqmw2IVJE4y9oKV9Uo3keNR9PnQ-G2KbdWbOMCkKnRnXKo0KDSQy5Wff9iKaf2AbskK~C7UEa8N6mk8CCeMGEJZj8JrKkOCiJy5gR~1LRM31EAFJqzUVbXznVY5wM1h8WS7ZT6ffLtdsRiLjtCP3m9xjpSICWAAqbPYD8ECDJ~dry3iMjl~voUwrDctT9T8E9CQrztfGw__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Thymic growth and increased T cells in Mx1-Cre p107-Single mice (Mx1-Cre Rblox/lox; p130lox/lox; p107+/−). (A, left) Representative control (Ctrl; top) and mutant (Mut; bottom) thymi (dashed lines). (right) H&E staining of representative control (top) and mutant (bottom) thymi. (B) Thymic cellularity (×107, log2 scale) of control and Mx1-Cre p107-Single mice after inactivation of the Rb family in young mice (n = 3 for each time point; asterisks indicate P < 0.05; ns indicates no significant difference; p-values: 3 wk = 0.35, 3 mo = 0.018, 5 mo = 0.04, and 7 mo = 0.03). Horizontal bars indicate the mean. (C) Comparison of thymic cellularity between control and Mx1-Cre Rb/p130 mutant mice at 3 wk (Ctrl: 29 ± 9.5 × 108 cells; Mx1-Cre Rb/p130: 38 ± 24.6 × 108 cells; P = 0.59; n = 3) and 16 wk (Ctrl: 7.6 ± 1.4 × 108 cells; Mx1-Cre Rb/p130: 10.8 ± 7.4 × 108 cells; P = 0.49; n = 3). (D) Oil Red O staining (red) on sections from 2-wk-old control (left), 9-mo-old control (middle), and 9-mo-old Mx1-Cre p107-Single mutant (right) thymi (performed on three mice each). Bars: (A) 200 µm; (D) 100 µm. (E) Quantification of intrathymic T cell progenitor populations between control and mutant mice (n = 3). Lineage-negative populations include CD25− cKit− (Ctrl: 48.65 ± 8.27%; Mut: 42.07 ± 12.95%; P = 0.54), CD25+ cKit− (Ctrl: 44.75 ± 2.90%; Mut: 53.37 ± 11.49%; P = 0.42), CD25− cKit+ (Ctrl: 3.08 ± 3.7%; Mut: 1.65 ± 1.64%; P = 0.45), and CD25+ cKit+ (Ctrl: 3.28 ± 1.28%; Mut: 2.65 ± 0.69%; P = 0.60). (F) Quantification of DN (Ctrl: 22.60 ± 0.82%; Mut: 17.33 ± 4.43%; P = 0.08), DP (Ctrl: 59.73 ± 3.98%; Mut: 73.61 ± 5.43%; P = 0.004), CD4+ T cell (Ctrl: 8.67 ± 0.83%; Mut: 5.00 ± 2.51%; P = 0.04), and CD8+ T cell populations (Ctrl: 8.93 ± 2.96%; Mut: 4.98 ± 1.91%; P = 0.03). (G) T cell BrdU incorporation 1 h after injection was quantified by FACS analysis (n = 3; p-values: Total = 0.002, DN = 0.14, DP = 0.05, CD4+ = 0.24, and CD8+ = 0.22). (H) Quantification of splenic naive T cells in mutants and control mice (n = 3 each; CD4+: Ctrl, 42.76 ± 5.81%; Mut, 55.06 ± 5.42% [P = 0.05]; CD8+: Ctrl, 50.14 ± 5.32%; Mut, 66.24 ± 3.64% [P = 0.03]). All error bars indicate standard error.
