Actinomycin D-induced phenocopies inDrosophila melanogasterand their relevance to the time of gene action

摘要

Drosophila melanogasterlarvae of a wild-type and a mutant stock, cultured in an axenic, chemically defined medium, were treated for one day with different concentrations of actinomycin D at different stages of development. Phenocopies affecting various organs of the adult occurred in different frequencies and in different patterns depending on the age at treatment. Assuming that the induced phenocopies were due primarily to the inhibition of DNA-dependent RNA synthesis by actinomycin D, the differential phenocopy effect indicates that: (1) Many genes which affect the differentiation of imaginal discs are activated in the third larval instar. (2) The developmental timing of gene activation in the third instar differs for various genes within a imaginal disc and in different imaginal discs.