THE PHO2 AND GCN4 TRANSCRIPTIONAL ACTIVATORS IN THE REGULATION OF ACID-PHOSPHATASES SYNTHESIS IN THE YEAST SACCHAROMYCES-CEREVISIAE

The possibility of substitution of the PHO2 activator protein by GCN4 protein in transcriptional regulation of acid phosphatase genes PHO5 and PHO11 was demonstrated in the yeast Saccharomyces cerevisiae. We observed the increase in acid phosphatase synthesis in the case of gcn4-DELTA-1 pho2-DELTA-1 mutant transformed with YCp88 (GCN4-wt) plasmid in comparison with that in nontransformed cells. The mode of repression of acid phosphatase synthesis in two types of transformants gcn4-Al pho2-DELTA-1 (GCN4-wt) and gcn4-DELTA-1 pho2-DELTA-1 (PHO2-wt) was studied. It wat demonstrated that repression of acid phosphatase synthesis in the first type of transformants took place at lower concentration of Pi than was necessary for the second type of transformants. The model of interactions between the GCN4 activator protein and PHO regulatory factors is proposed.