REPRESENTATIONAL DIFFERENCE ANALYSIS OF A COMMITTED MYELOID PROGENITOR-CELL LINE REVEALS EVIDENCE FOR BILINEAGE POTENTIAL

In this study we have sought to characterize a committed myeloid proge nitor cell line in an attempt to isolate general factors that may prom ote differentiation. We used cDNA representational difference analysis (RDA), which allows analysis of differential gene expression, to comp are EML and EPRO cells. We have isolated nine differentially expressed cDNA fragments as confirmed by slot blot, Northern, and PCR analysis. Three of nine sequences appear to be novel whereas the identity of th e remaining fragments suggested that the EPRO cell line is multipotent , Among the isolated sequences were eosinophilic, monocytic, and neutr ophilic specific genes. Therefore, we tested the ability of EPRO cells to differentiate along multiple myeloid lineages and found that EPRO cells exhibited morphologic maturation into either monocyte/macrophage s or neutrophils, but not eosinophils, Furthermore, when EPRO cells we re exposed to ATRA, neutrophil specific genes were induced, whereas mo nocytic markers were induced by phorbol ester treatment, This study hi ghlights the use of cDNA RDA in conjunction with the EML/EPRO cell lin e to isolate markers associated with macrophage and neutrophil differe ntiation and establishes the usefulness of this system in the search f or factors involved in myeloid commitment.