Accumulation of porphobilinogen deaminase, uroporphyrinogen decarboxylase, and alpha- and beta-globin mRNAs during differentiation of mouse erythroleukemic cells. Effects of succinylacetone.

We have monitored, during the dimethyl sulfoxide (Me2SO)-induced differentiation of MEL cells, the accumulation of mRNAs encoding two enzymes of the heme biosynthetic pathway, namely porphobilinogen deaminase and uroporphyrinogen decarboxylase. Our results demonstrate that the induction of these two enzymes is accounted for by a coordinate increase in their corresponding mRNAs, as estimated by hybridization with specific cloned cDNA probes. These events occur early during the differentiation process and precede the accumulation of alpha- and beta-globin mRNAs. Blocking the heme biosynthetic pathway with succinylacetone does not appear to modify the Me2SO-mediated increase of porphobilinogen deaminase and uroporphyrinogen decarboxylase mRNAs although succinylacetone has been shown to prevent the induction of immunoreactive porphobilinogen deaminase as well as its enzymatic activity (Beaumont, C., Deybach, J. C., Grandchamp, B., Da Silva, V., de Verneuil, H., and Nordmann, Y. (1984) Exp. Cell Res. 154, 474-484). Heme depletion resulting from the presence of succinylacetone in the culture medium reduces the extent of the Me2SO-mediated accumulation of alpha- and beta-globin mRNAs, and this effect is reversed by the addition of 10 microM exogenous hemin. Although the presence of succinylacetone prevents hemoglobinization of MEL cells, it does not prevent MEL cells from losing their proliferative capacity when treated with Me2SO.