title: Prompt heat-shock and heat-shifted proteins associated with the nuclear matrix-intermediate filament scaffold in Drosophila melanogaster cells.
abstract: Elevated temperatures induced the synthesis of several new proteins in Drosophila melanogaster cells. Besides the conventional heat shock (HS) proteins, another set of temperature-induced proteins has been found. These latter resemble the prompt HS proteins of mammalian cells. The prompt HS proteins of Drosophila differ from the well-known conventional HS proteins in the following properties: (1) synthesis of the prompt HS proteins is insensitive to the transcription inhibitor actinomycin D, which blocks the appearance of conventional HS proteins; (2) induction of the prompt HS proteins requires a significantly higher temperature than conventional HS proteins; (3) prompt HS proteins associate strictly with the nuclear matrix-intermediate filament complex (NM-IF), while the conventional HS proteins are found in all subcellular fractions; (4) prompt HS proteins of Drosophila are induced by high temperature alone while the conventional HS proteins are also produced by a variety of stress conditions. Resinless-section electron micrographs show an altered nuclear matrix morphology in heat-shocked cells. The nuclear matrix fibers are altered in spatial distribution and have much additional electron-dense material. This added material probably reflects the soluble proteins shifted into the nuclear matrix at high temperature. The prompt HS proteins can be distinguished clearly from heat-shifted proteins by several criteria. Also, the prompt HS proteins are distinct from the heat-insensitive viral proteins of a persistent virus (HPS-1).
authors.affiliation: Department of Biology, Princeton University, New Jersey 08544.
authors.forename: D A
authors.initials: DA
authors.lastname: Ornelles
authors.forename: S
authors.initials: S
authors.lastname: Penman
mesh_terms: D000818:Animals; D004331:Drosophila melanogaster / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D006358:Hot Temperature; D007381:Intermediate Filament Proteins / Q000096:biosynthesis*; D007382:Intermediate Filaments / Q000648:ultrastructure; D008854:Microscopy, Electron; D015530:Nuclear Matrix / Q000378:metabolism* / Q000648:ultrastructure; D009687:Nuclear Proteins / Q000096:biosynthesis*
chemical_list: D006360:Heat-Shock Proteins; D007381:Intermediate Filament Proteins; D009687:Nuclear Proteins