Abstract
In Chironomus tentans salivary gland cells, the cytoplasm can be dissected into concentric zones situated at increasing distances from the nuclear envelope. After RNA labeling, the newly made ribosomal subunits are found in the cytoplasm mainly in the neighborhood of the nucleus with a gradient of increasing abundance towards the periphery of the cell. The gradient for the small subunit lasts for a few hours and disappears entirely after treatment with puromycin. The large subunit also forms a gradient but one which is only partially abolished by puromycin. The residual gradient which which is resistant to the addition of the drug is probably due to the binding of some large ribosomal units to the membranes of the endoplasmic reticulum (J.-E. Edstrom and u. Lonn. 1976. J. Cell Biol. 70:562-572, and U. Lonn and J.-E. Edstrom. 1976. J. Cell. Biol. 70:573-580). If growth is inhibited by starvation, only the puromycin-sensitive type gradient is observed for the large subunit, suggesting that the attachment of these newly made subunits to the endoplasmic reticulum membranes will not occur. If, on the other hand, the drug-resistant gradient is allowed to form in feeding animals, it is conserved during a subsequent starvation for longer periods than in control feeding animals. This observation provides a further support for an effect of starvation on the normal turnover of the large subunits associated with the endoplasmic reticulum. These results also indicate a considerable structural stability in the cytoplasm of these cells worth little or no gross redistribution of cytoplasmic structures over a period of at least 6 days.
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Selected References
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- BEERMANN W. [A Balbiani ring as locus of a salivary gland mutation]. Chromosoma. 1961;12:1–25. doi: 10.1007/BF00328911. [DOI] [PubMed] [Google Scholar]
- Blobel G., Dobberstein B. Transfer of proteins across membranes. I. Presence of proteolytically processed and unprocessed nascent immunoglobulin light chains on membrane-bound ribosomes of murine myeloma. J Cell Biol. 1975 Dec;67(3):835–851. doi: 10.1083/jcb.67.3.835. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Boshes R. A. Drosophila polyribosomes. The characterization of two populations by cell fractionation and isotopic labeling with nucleic acid and protein precursors. J Cell Biol. 1970 Sep;46(3):477–490. doi: 10.1083/jcb.46.3.477. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Darrow J. M., Clever U. Chromosome activity and cell function in polytenic cells. 3. Growth and replication. Dev Biol. 1970 Mar;21(3):331–348. doi: 10.1016/0012-1606(70)90128-4. [DOI] [PubMed] [Google Scholar]
- Doyle D., Laufer H. Sources of larval salivary gland secretion in the dipteran Chironomus tentans. J Cell Biol. 1969 Jan;40(1):61–78. doi: 10.1083/jcb.40.1.61. [DOI] [PMC free article] [PubMed] [Google Scholar]
- FLECK A., MUNRO H. N. The precision of ultraviolet absorption measurements in the Schmidt-Thannhauser procedure for nucleic acid estimation. Biochim Biophys Acta. 1962 May 14;55:571–583. doi: 10.1016/0006-3002(62)90836-3. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Lande M. A., Adesnik M., Sumida M., Tashiro Y., Sabatini D. D. Direct association of messenger RNA with microsomal membranes in human diploid fibroblasts. J Cell Biol. 1975 Jun;65(3):513–528. doi: 10.1083/jcb.65.3.513. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ringborg U., Rydlander L. Nucleolar-derived ribonucleic acid in chromosomes, nuclear sap, and cytoplasm of Chironomus tentans salivary gland cells. J Cell Biol. 1971 Nov;51(21):355–368. doi: 10.1083/jcb.51.2.355. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rubinstein L., Clever U. Chromosome activity and cell function in polytenic cells. V. Developmental changes in RNA synthesis and turnover. Dev Biol. 1972 Apr;27(4):519–537. doi: 10.1016/0012-1606(72)90190-x. [DOI] [PubMed] [Google Scholar]