RNA synthesis in the Drosophila melanogaster puffs

Autoradiographical analysis of [3H]-uridine incorporation into three large puffs of Drosophila melanogaster has revealed that after 1 min pulse with isotope the label is observed above the whole puff area. When puffs were induced by high temperature, RNA synthesis was sharply increased (or started) in many sites of the developing puff. No significant delay in the transport of newly-synthesized RNA in large puffs, in comparison with small ones, has been found. In regions without temperature-induced puffs RNA synthesis and its transport are apparently delayed under influence of heat shock.