FIG 4.

ShcA is required for pre-TCR-dependent proliferation. (A) Proliferation measured by determinations of BrdU uptake and 7-AAD signal levels in DN3, DN4, and DP thymic subsets from the different transgenic mouse strains. (B and C) The relative numbers of DN3L cells within each of the cell cycle-defective phases are plotted as the averages of the means of the numbers of cells ± SD. Data were obtained from 3- to 6-week-old littermates for each genotype. (D) Levels of proliferation of KJ1.26-positive DN3, DN4, and DP thymic subsets in DO11.10/ShcFFF and DO11.10/Lck-Cre/ShcFFF transgenic mice were assessed by BrdU uptake as described in Materials and Methods (n = 4).