Figure 4.

Leukemic pre-B cells express Notch receptors, ligands and target genes. RT-PCR results for Notch receptors, ligands and target genes in blasts from (a) three precursor-B ALL patients and normal peripheral blood B cells, (b) B lineage cell lines or (c) normal peripheral blood B cells. (d) Western blots results at left detect JAG1 and DLL4 in 697 cell lysates. Results at right report relative distribution of Notch1, Notch2 and Notch3 ICNs between cytoplasmic and nuclear fractions prepared from 697 cells, ±GSI treatment. SP1 and Hsp90 serve as controls for nuclear and cytosol fractions. Note that a truncated form of SP1 is found in the nucleus of GSI-I-treated cells, consistent with induction of apoptosis.