Differential distribution of nonhistone proteins from polytene chromosomes of Drosophila melanogaster after heat shock.

Nine monoclonal antibodies directed against chromosomal proteins of D. melanogaster were used to study, by indirect immunofluorescence, the distribution of their respective antigens on polytene chromosomes following heat shock. This treatment is known to induce a specific set of transcriptionally active puffs with concomitant reduction of transcriptional activity in previously active loci. Our studies revealed wide differences in the distribution of the individual chromosomal proteins under heat shock conditions with regard to pattern and rate of both elimination from the inactivated loci and accumulation in the activated loci.