title: Differential expression of heat-shock proteins and spontaneous synthesis of HSP70 during the life cycle of Blastocladiella emersonii.
abstract: The heat-shock response in Blastocladiella emersonii is dependent on the developmental stage. Cells exposed to elevated temperatures at different stages of the life cycle (sporulation, germination or growth) show a differential synthesis of heat-shock proteins (hsps). Of a total of 22 polypeptides induced, particular subsets of hsps appear in each phase, demonstrating a non-coordinate heat-shock gene expression. In contrast, heat-shock-related proteins (hsp76, hsp70, hsp39a) are spontaneously expressed at a high level during sporulation. By the criteria of two-dimensional gel electrophoresis and partial proteolysis mapping, the 70,000-Da protein, whose synthesis is induced spontaneously during sporulation, is indistinguishable from the heat-inducible hsp70. The techniques of in vitro translation, and Northern analysis using a Drosophila hsp70 probe, demonstrated that enhanced synthesis of hsp70, which occurs during heat-shock treatment and spontaneously during sporulation, is associated with an accumulation of hsp70 mRNA. These observations suggest that hsp70 gene expression is induced during sporulation.
mesh_terms: D001754:Blastocladiella / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D002453:Cell Cycle; D008411:Chytridiomycota / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D007120:Immunochemistry; D010449:Peptide Mapping; D012331:RNA, Fungal / Q000032:analysis; D013172:Spores, Fungal; D013696:Temperature; D014158:Transcription, Genetic
chemical_list: D006360:Heat-Shock Proteins; D012331:RNA, Fungal