Figure 2.
IL-7 down-regulates p27Kip1 posttranslationally. (A) D1 cells were cultured with (+) or without (−) IL-7 for 12 h. Cell lysates were resolved by SDS-PAGE and immunoblotted with antibodies against p27Kip1, p16, and β-actin. (B) LN T cells were isolated and grown with or without IL-7 for 24 h. Protein levels were measured by immunoblotting using antibodies against p27Kip1, p16, p21Cip1, and β-actin. (C) Cell lysates were prepared from D1 or bcl-2–transfected D1 cells cultured with or without IL-7 for 12 h. p27Kip1 protein level was measured by immunoblotting. (D) D1 cells were cultured with (+) or without (−) IL-7 for 12 h. Total RNAs were isolated and 20 μg total RNA was loaded to agarose gel (bottom). The RNA blot was probed with 32P-labeled p27Kip1 cDNA fragment (top).