Parallel changes in puffing activity and patterns of protein synthesis in salivary glands of Drosophila.

Abstract

The The pattern of puffing activity in the polytene chromosomes of Drosophila, and other Diptera, changes in a complex way during development. During late larval and "prepupal" development, at least, these changes are under hormonal control (1, 2). Puffing activity can also be controlled by certain environmental treatments; in particular a brief exposure of salivary glands, either in the intact animal or in culture, to high temperature induces specific puffs (3-5).We report the changes in salivary gland protein synthesis that result from temperature shock and the correlated changes in puffing activity. They will enable a formal proof of the hypothesis that puffs are active gene loci (6), a proof that demands the genetic mapping of a putative puff product to the puff itself and the demonstration that mutations which specifically result in the loss of the puffs also result in the absence of its putative product. Preparation of Samples. At the end of the labeling period the radioactive medium was removed with a fine-tipped glass pipette and the glands were flooded with medium containing a 100-fold excess of nonradioactive methionine. If necessary they were then stored at -70°to await further processing. After the wash in nonradioactive medium the glands were washed in cold 10% trichloroacetic acid and then transferred into small glass test tubes. Then they were washed with 10% cold trichloroacetic acid (20 min Control Experiments. The extraction procedure we used is essentially that of Tissieres et al. (9). We have varied the extraction method (for example by using boiling 10% trichloroacetic acid or prolonged chloroform:methanol extraction at 60°) without affecting the results. We have also studied the possible effects of sodium dodecyl sulfate on protease activity by treatment of samples with either phenyl methyl sulfonyl fluoride (10) or L-1-tosylamido-2-phenylethylchlo-3604

Acetylation and methylation patterns of core histones are modified after heat or arsenite treatment of Drosophila tissue culture cells

“…This stress leads to the synthesis of a number of RNAs (3-7),several of which code for new polypeptide chains, the heat shock proteins (8)(9)(10), while the synthesis of most other RNAs is repressed (3)(4)(5)(6)(7). This phenomenon appears to be general, as it has been observed in a great variety of organisms, from E.coli to man (11).…”

Primary sequence of the 5′ flanking regions of the Drosophila heat shock genes in chromosome subdivision 67B

“…The transcription of most active genes is suppressed, while a small set is activated. Also, translation of pre-existing mRNAs ceases and the heat shock induced proteins are synthesized in large amounts (2,3,4). A rapid response to heat shock is the breakdown of almost all polysomes (3,5).…”

The Pattern of Protein Synthesis Induced by Heat Shock of HeLa Cells

“…Some of these RNAs are preferentially translated into a set of polypeptides known as the heat-shock polypeptides [4]. Unlike the puffing, the synthesis of the heat-shock polypeptides is detected 10 min after the start of the heat shock and continues for several hours afterwards [5].…”