[Determination of gene Est-6 expression in the genitalia of Drosophila melanogaster males].

To determine the time of the appearance of cells capable of subsequent synthesis of esterase-6, genital imaginal discs extracted from male larvae of different instars were transplanted in female larvae just before pupation. An analysis of the esterase activity in transplants has shown that cells in which esterase-6 is to be synthesized appear 8-10 hrs after the beginning of the 3rd larval instar, i.e. long before the differentiation starts. The relations between the determination of the gene Est-6 expression and its transcription and translation were assessed by studying the effect of the inhibitors of RNA (actinomycin D) and protein synthesis (cycloheximide). It has been demonstrated that the transcription and translation of the gene Est-6 take place after metamorphosis during the first hours after emergence of imago. There exists, thus, a large interval between the appearance of cells capable of esterase synthesis and the time of expression of the structural gene controlling this enzyme. The data obtained suggest that cell determination may not be due to the accumulation of "long-living" templates (mRNA).