Specific Intranucleolar Distribution of Hsp70 during Heat Shock in Polytene Cells

摘要: Abstract Hsp70, the most abundant and conserved heat shock protein, has been described as strongly concentrating in nucleolus during shock. The important metabolic processes that take place nucleolus, rDNA transcription, processing, assembling with ribosomal proteins, nucleolar architecture itself are very sensitive to temperature changes. In this work, we have analyzed detail changes, structure activity, induced by Chironomus thummi salivary gland cells fine subnucleolar localization of Hsp70 optimum chosen induce response was 35°C. Under these conditions transcription genes, inactivation previously active genes maximum synthesis Hsps place, while survival larvae recovery were ensured. After 1 h at 35°C, nucleoli change from a uniform control pattern segregated components can be observed even light microscopic level. dense fibrillar component (DFC) granular appeared perfectly differentiated spatially separated, former occupying mainly central inner region surrounded rim component. specifically localized within DFC upon shown immunolocalization both electron microscopy. Pulse labeling [ 3 H]uridine proves rRNA continues distribution correlates newly produced transcripts. also colocalizes RNA polymerase I, being restricted DFC. These data show seems intranucleolar target for heat-shocked cells. We discuss results relation possible function first steps preribosome synthesis.