The analysis of a temperature-sensitive (ts) mutation influencing the expression of heat shock-inducible genes in Drosophila melanogaster.

The effect of a ts-mutation belonging to the cell-lethal type on protein and RNA synthesis under heat shock conditions has been investigated. The mutation studied, l(l)ts-403, localized in the X-chromosome has significant effect on the kinetics of protein synthesis in salivary gland subjected to heat treatment under in vivo and in vitro conditions. The animals homozygous for l(l)ts-403 are characterized by a rapid drop of label incorporation into heat shock proteins. It is shown that the mutation affects not only the kinetics of heat-shock proteins synthesis but their electrophoretic pattern as well. The experiments performed enable us to conclude that the presumptive regulatory gene realized its action at the level of transcription of heat shock loci.