DIFFERENTIAL EXPRESSION OF PROTEIN-KINASE-C ISOFORM GENES IN 3 MURINEERYTHROLEUKEMIA CELL VARIANTS - IMPLICATION FOR CHEMICAL-INDUCED DIFFERENTIATION

The presence of alpha, delta, epsilon, theta, and zeta protein kinase C isoforms in DS19 murine erythroleukemia cells has been established i n this study. In addition, the mRNA levels of these isozymes have been measured by quantitative reverse transcriptase-polymerase chain react ion. Isoform delta has been found to be the most abundant isotype, whe reas isoform zeta resulted to be present in only few copies. Furthermo re, the expression levels of all five protein kinase C isozymes have b een studied in three cell clones, derived from parental DS19 cells and characterized by different susceptibilities to differentiation. This comparative analysis indicated that the calcium-independent isozymes ( delta, epsilon, zeta and theta) display significantly higher expressio n levels in cells less prone to differentiation. On the other hand, th e mRNA levels of the only calcium-dependent isoform present (alpha) fl uctuate poorly from one cell clone to the other, but are the highest i n the cell clone characterized by the fastest rate of differentiation. This study represents the first complete characterization of the basa l levels of specific protein kinase C isotypes in different murine ery throleukemia cell clones and provides further evidence for the role of individual isozymes in the early events that trigger chemical induced murine erithroleukemia cell differentiation. (C) 1994 Academic Press, Inc.