FIG. 2.
Cyclin D1 levels are posttranscriptionally upregulated in M4 AML, M5 AML, and bcCML patients. (A) Whole-cell lysates were analyzed by Western blot (W.B.) as indicated. The levels of cyclin D1 are increased in all leukemia specimens (lanes 2, 3, and 5 to 8). β-Actin is shown as a control for protein loading. (B) Northern blot (N.B.) analysis of whole-cell lysates shows upregulation of cyclin D1 mRNA levels in cells derived from M1 AML, M2 AML, M2/AML-ETO AML, and ALL patients (lanes 4 to 7). Cyclin D1 mRNA levels were not altered in M4 AML, M5 AML, and bcCML specimens (lanes 2, 3, 9, and 10). (C) RNA, isolated from nuclear (n) and cytoplasmic (c) fractions, was analyzed by Northern blot as indicated. Nuclear export of cyclin D1 mRNA was increased in the cells derived from M5 AML (lanes 3, 4, 9, and 10) and bcCML (lanes 5 and 6) patients. tRNALys and U6snRNA were used as markers for the cytoplasmic and nuclear fractions, respectively. GAPDH is shown as a control for RNA loading. Samples are labeled as described in Fig. 1.