Impaired thymocyte development in the absence of RhoH. (A) Thymocytes of 2-month-old mice were analyzed for the expression of CD4 and CD8 by FACS. Bar graph presents the absolute cell number of each population. **P < .01; ***:P < .001. Error bars show the standard deviation (n [control]/[RhoH−/−]: 11/11). (B) Thymocytes of 2-month-old mice were gated for lineage-negative (B220, CD4, CD8, NK1.1, Mac1, Gr-1, Ter119) cells and analyzed for the expression of CD25 and CD44. DN1, CD25−CD44+; DN2, CD25+CD44+; DN3, CD25+CD44−; DN4, CD25−CD44−. Bar graph presents the absolute cell number of each population. *P < .05. Error bars show the standard deviation (n [control]/[RhoH−/−]: 4/4).