Specific induction of the 93D puff in Drosophila melanogaster by a homogenate of heat shocked larval salivary glands

Abstract

The effect of a homogenate of heat-shocked (60 min at 37°C) larval salivary glands (HSGH) of D. melanogaster on the activity of the different heat shock puff loci in fresh salivary glands has been examined by ³H-uridine autoradiography. A 45 min incubation of fresh glands in HSGH results in induction of only the 93D puff without a concurrent induction of the other eight heat shock puff loci. Other chromosomal and nucleolar RNA synthesis is not affected. A 20 min heat shock at 37°C to glands preincubated in HSGH causes a typical induction of all the other eight heat shock puff loci; the 93D puff activity in these doubly treated glands is slightly less than in only HSGH incubated glands. These observations are discussed in relation to regulation of the 930 puff activity.