[Change of WT1 Gene Expression during Induction of Differentiation of NB4 Cell Line]

In order to study the relation between WT1 gene expression and differentiation of NB4 leukemic cells, a competitive RT-PCR method was established by using recombinant DNA technique to detect the expression of WT1 gene quantitatively during differentiation of NB4 leukemic cells induced by retinoic acid. The expression of CD11b was simultaneously determined by an indirect immunofluorescence staining technique and flow cytometry. Our results showed that WT1 gene expression rapidly decreased during the differentiation of NB4 cells. The molecular number of WT1 gene in 1 micro g total RNA was 4 x 10(6), 1.56 x 10(6) and 0.4 x 10(6), respectively, prior to and at 12 or 24 hours after exposure to retinoic acid, and it was in accordance with the change of CD11b. These data suggest that the abnormally high expression of WT1 gene in leukemic cells was associated with the block of cell differentiation. The detection of WT1 expression with competitive RT-PCR combined with measure of CD antigens will contribute to study on the differentiation induction of leukemic cells.