Requirement for Vav proteins in cell-cycle progression. (A) B cells of the indicated genotypes were stained with CFDA-SE and cultured in the presence of 1 μg/mL LPS (left) or 5 μg/mL anti-CD180 (right). The first and third panels show analyses of cells gated for lymphocytes by forward and side scatter of CFDA-SE fluorescence after 72 hours of culture; numbers of divisions are indicated. The second and fourth panels show cell-cycle analyses of PI staining after 48 hours of culture; percentage of cells in G₁ and G₂/S/M phases are given. CFSE indicates carboxyfluorescein diacetate succinimidyl ester. (B) B cells from WT or Vav1/2^-/- mice were loaded with CFDA-SE and cultured with or without 1 μg/mL LPS. After 48 hours, cells were harvested, stained with TO-PRO-3, and analyzed by FACS. Results from a representative mouse of each genotype are displayed. The boxes indicate live cells identified as TO-PRO-3 negatives. CM indicates culture medium. (C) The graph shows the percentage of live cells from 3 WT (○) or 3 Vav1/2^-/- mice (•) after culture with or without LPS for 48 hours. Statistical significance was determined using the Student t test. Error bars represent the mean of the 3 values.