Cell
ArticleEffect of heat shock on the synthesis of low molecular weight RNAs in drosophila: Accumulation of a novel form of 5S RNA
Abstract
The synthesis and stability of low molecular weight RNAs following heat shock in Drosophila melanogaster cell cultures have been examined. When cultures are raised from 25°C to 37°C, the synthesis of tRNA and at least two other low molecular weight RNAs continues at the 25°C rate. 5.8S ribosomal RNA and most of the low molecular weight nuclear RNAs are not synthesized. The synthesis of 5S ribosomal RNA is greatly reduced. A large amount of an RNA of about 135 nucleotides in length accumulates at 37°C. Nucleotide sequence analysis reveals that this RNA is a novel form of 5S RNA with approximately 15 additional nucleotides at its 3′ end.
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Polytene chromosomes: 70 Years of genetic research
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Ultrastructural localization of Hsp-72 examined with a new polyclonal antibody raised against the truncated variable domain of the heat shock protein
1999, Cell Stress and ChaperonesIn spite of the intensive search for the determination of the continuously widening physiological and pathological roles of different stress proteins, their ultrastructural localization at the electron microscopic (EM) level has hardly been examined. As it becomes increasingly evident that the function and physiological effectiveness of stress proteins are highly dependent on their spatial location and their associations with diverse regulator proteins, the demand for morphological studies which can identify their detailed distribution within the cells is evident. The reason for the practical lack of studies carried out at the EM level, lies in the shortage of reagents with suitable specificity and avidity necessary for this type of examination. To create such a reagent, a polyclonal antibody was raised using a recombinant truncated form of the inducible Hsp-72 protein. The antibody was extensively characterized, using different immunochemical methods to determine and verify its specificity, and then it was tried in ultrastructural examinations. Using the new antibody, it was possible to analyze the intracellular distribution of Hsp-72 with the immunogold technique. The localization of Hsp-72 was demonstrated directly at the ultrastructural level in the cytoplasm (especially at the cisterns of the RER), in the nucleus (mainly around the heterochromatic regions) and at both sides of the nuclear envelope close to the membrane pores. Apart from these localizations, Hsp-72 was found in several membrane bordered intracellular structures, which mainly belong to the endosomal-lysosomal system. We provide the first morphological verification of the appearance of Hsp-72 on the surface of the cells. Also novel is the indication, that the stress protein may recycle from the cell surface using a common route which includes coated pits and the endosomal system.
Genetic Organization of Polytene Chromosomes
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Neemazal, a product of neem (Azadirachta indica), induces resistance in pea (Pisum sativum) against Erysiphe pisi
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This study reports the cloning, characterization and identification of a previously undetected ribosomal RNA in Drosophila melanogaster. The ribosomal RNA is 370 nucleotides in length and contains the 5.8S and 2S ribosomal RNA coding regions. Analysis of polysome-containing cell extracts indicates that the RNA is present on polysomes suggesting a functional role within the ribosome. Northern blot analysis indicates that the RNA is also present in adult Drosophila melanogaster flies.