Sequential induction of heme pathway enzymes during erythroid differentiation of mouse Friend leukemia virus-infected cells.

Abstract

The process of erythroid differentiation in mouse Friend leukemia virus transformed cells (T3-C1-2) was examined by following changes in several enzyme activities of the heme biosynthetic pathway and in heme concentration while the cells were undergoing erythroid differentiation after treatment with dimethylsulfoxide. Untreated cells on the one hand, have a limited capacity for spontaneous differentiation. On the other hand, dimethylsulfoxide(DMSO)-treated cells showed an increase in the activities of delta-aminolevulinic acid (ALA) synthetase, ALA dehydratase, uroporphyrinogen-I synthetase, ferrochelatase, and heme concentration by days 1, 1.5, 2, and 4, respectively. The increase of the heme pathway enzymes and heme concentration followed the order of these enzymes or products as they are arranged in the heme biosynthetic pathway. These changes induced by DMSO were effectively inhibited by treatment with actinomycin D, suggesting that continued RNA synthesis is required for the differentiation process. 5-bromo-2'-deoxyuridine (BrdU) (10(-5) M) inhibited the DMSO-induced changes of the heme pathway enzymes. BrdU was most effective when it was present during the first 2 days of cell culture. It gradually lost its inhibitory effect when added after the 3rd day or later. The BrdU-mediated inhibition was completely overcome by the addition of thymidine (7 x 10(-5) M), but not by uridine (7 x 10(-5) M). All these data suggest that a sequential induction of the heme pathway enzyme takes place during erythroid differentiation of Friend leukemia cells, and that the sequential induction of the enzymes may be due to a sequential activation of genes coding for these enzyme activities.

Balanced globin protein expression and heme biosynthesis improve production of human hemoglobin in Saccharomyces cerevisiae

“…The intracellular heme concentration was measured using a protocol derived from (Sassa, 1976) and 175 slightly modified from (Michener et al, 2012). Cells were grown to a desired density and harvested at 176 OD 600 *mL =8 (e.g.…”

Molecular and Genetic Characterization of Ferrochelatase.

“…In MEL cells induced with DMSO enzyme activities of the heme biosynthetic pathway and hemoglobin biosynthesis increased (Friend et al 1971;Sassa 1976). Studies with MEL cells have resulted in many ideas concerning erythroid differentiation.…”

Destruction of erythroleukaemic cells by photoactivation of endogenous porphyrins

“…In addition, protoporphyrin is biosynthesized in low amounts, by all tumour cells, as well as non-transformed tissues, while in specific transformed cells such as erythroleukaemia, it can be produced more efficiently (Marks & Rifkind, 1978). In their proerythroblastic phase the enzymatic activity of porphyrin biosynthesis was found to be constitutive, except for the first enzyme, the ALA-synthase which is the rate limiting step of the pathway and is inducible (Sassa, 1976), and iron uptake from transferrin (Lasky et al, 1986). Therefore, in order to induce porphyrin synthesis by erythroblasts, exogenous 5-ALA must be supplied to circumvent the first limiting enzyme .…”