[Study of the maternal effect on genes coding 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase...

The maternal effect of two pentose cycle enzymes, 6-phosphogluconate dehydrogenase (6PGD) and glucose-6-phosphate dehydrogenase (G6PD) was investigated using a genetical system based on the interaction of Pgd- and Zw- alleles, inactivating 6PGD and G6PD respectively. The presence of enzymes and their formation in individuals free of maternal encoding genes was studied. Maternal forms of enzymes, which can be revealed under the pupa stage, were detected. The activity of maternal 6PGD and G6PD, calculated per one individual, grows 20--30-fold since the egg stage to the III larval age even in the absence of normal Pgd and Zw genes. The immunological studies have shown that the growth of 6PGD activity is defined by an increase in the number of molecules of maternal type enzyme. A hybrid isozyme arising from integration of isozyme subunits, controlled by the maternal genes and those of embryo itself, was found. All this is evidence to the fact that the maternal effect in the 6PGD case is due to a long-life stable in mRNa, transfered along with the egg cytoplasm and translated in the course of Drosophila melanogaster development.