Ratios between the abundance of messenger RNA and the corresponding protein of two growth-related genes, c-myc and vimentin, in leukemia blast cells.

The abundance of the mRNAs of two growth-related genes, vimentin and c-myc, and that of the corresponding proteins have been studied in unstimulated and phytohemagglutinin-stimulated lymphocytes as well as in 18 populations of leukemic blast cells. The quantitative assay was carried out by densitometric scanning of Northern and Western blots. In normal lymphocytes the mRNA and the protein of both genes were almost undetectable. The phytohemagglutinin stimulation led to a sharp increase of the mRNA and the proteins of vimentin and c-myc. The increase was followed by a progressive fall of the gene products. The rate of decrease of the two mRNAs was similar to that of the corresponding proteins. In some leukemic populations very similar amounts of the vimentin protein were accompanied by amounts of the mRNA differing at least 25 times. Not unlikely, very similar amounts of p62c-myc corresponded to mRNA abundances differing at least 16 times. The coordinated biogenesis of both messenger RNAs and proteins, which occurs in mitogen-stimulated lymphocytes, is substituted, in approximately 30% of the leukemic blast cell populations, by molecular events leading to the accumulation of an excess of mRNA.