Abstract
The fine structure and cytochemistry of the extremely large RNA puffs, or Balbiani rings, in salivary gland nuclei of midge, Chironomus thummi, larvae have been investigated. The Balbiani rings are composed of a diffuse mass of electron-opaque 400 to 500 A granules, short threads about 180 to 220 A in diameter and associated fine chromatin fibrils. These components appear to be organized into brushlike elements which form the ring. Electron microscope cytochemistry has shown that the granules and short threads contain RNA. After ribonuclease digestion, only 50 to 100 A chromatin fibrils were apparent in the Balbiani ring, and the granules were no longer demonstrable. Deoxyribonuclease digestion had no apparent effect on these structures. Observations indicate that the granules are formed from the short threads and released into the nucleoplasm in which they are evenly distributed. At the nuclear envelope, many granules have been observed partially or completely within the nuclear pores. These granules become elongated and are shown to penetrate the center of the pore in a rodlike form, about 200 A in diameter. The Balbiani ring granules are not normally visible within the cytoplasm adjacent to the nuclear envelope, but have been rarely found in this region. It is suggested that the granules represent the product of the Balbiani ring, possibly a messenger RNA bound to protein, and that they regularly pass into the cytoplasm through a narrow central channel in the pores of the nuclear envelope.
Full Text
The Full Text of this article is available as a PDF (2.8 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- AFZELIUS B. A. The ultrastructure of the nuclear membrane of the sea urchin oocyte as studied with the electron microscope. Exp Cell Res. 1955 Feb;8(1):147–158. doi: 10.1016/0014-4827(55)90051-3. [DOI] [PubMed] [Google Scholar]
- ANDERSON E., BEAMS H. W. Evidence from electron micrographs for the passage of material through pores of the nuclear membrane. J Biophys Biochem Cytol. 1956 Jul 25;2(4 Suppl):439–444. doi: 10.1083/jcb.2.4.439. [DOI] [PMC free article] [PubMed] [Google Scholar]
- BEERMANN W., BAHR G. F. The submicroscopic structure of Balbiani-ring. Exp Cell Res. 1954 Feb;6(1):195–201. doi: 10.1016/0014-4827(54)90161-5. [DOI] [PubMed] [Google Scholar]
- BEERMANN W., CLEVER U. CHROMOSOME PUFFS. Sci Am. 1964 Apr;210:50–58. doi: 10.1038/scientificamerican0464-50. [DOI] [PubMed] [Google Scholar]
- BEERMANN W. Nuclear differentiation and functional morphology of chromosomes. Cold Spring Harb Symp Quant Biol. 1956;21:217–232. doi: 10.1101/sqb.1956.021.01.018. [DOI] [PubMed] [Google Scholar]
- FELDHERR C. M. THE EFFECT OF THE ELECTRON-OPAQUE PORE MATERIAL ON EXCHANGES THROUGH THE NUCLEAR ANNULI. J Cell Biol. 1965 Apr;25:43–53. doi: 10.1083/jcb.25.1.43. [DOI] [PMC free article] [PubMed] [Google Scholar]
- GALL J. G. Small granules in the amphibian oocyte nucleus and their relationship to RNA. J Biophys Biochem Cytol. 1956 Jul 25;2(4 Suppl):393–396. doi: 10.1083/jcb.2.4.393. [DOI] [PMC free article] [PubMed] [Google Scholar]
- GOLDSTEIN L. Localization of nucleusspecific protein as shown by transplantation experiments in Amoeba proteus. Exp Cell Res. 1958 Dec;15(3):635–637. doi: 10.1016/0014-4827(58)90118-6. [DOI] [PubMed] [Google Scholar]
- Goldstein L., Plaut W. DIRECT EVIDENCE FOR NUCLEAR SYNTHESIS OF CYTOPLASMIC RIBOSE NUCLEIC ACID. Proc Natl Acad Sci U S A. 1955 Nov 15;41(11):874–880. doi: 10.1073/pnas.41.11.874. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KEYL H. G. Untersuchungen am Karyotypus von Chironomus thummi. I. Karte der Speicheldrüsen-Chromosomen von Chironomus thummi thummi und die cytologische Differenzierung der Subspezies Ch. th. thummi und Ch. th. piger. Chromosoma. 1957;8(6):739–756. [PubMed] [Google Scholar]
- LOEWENSTEIN W. R., KANNO Y. The electrical conductance and potential across the membrane of some cell nuclei. J Cell Biol. 1963 Feb;16:421–425. doi: 10.1083/jcb.16.2.421. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Latham H., Darnell J. E. Entrance of mRNA into HeLa cell cytoplasm in puromycin-treated cells. J Mol Biol. 1965 Nov;14(1):13–22. doi: 10.1016/s0022-2836(65)80225-x. [DOI] [PubMed] [Google Scholar]
- McConkey E. H., Hopkins J. W. Subribosomal particles and the transport of messenger RNA in HeLa cells. J Mol Biol. 1965 Nov;14(1):257–270. doi: 10.1016/s0022-2836(65)80245-5. [DOI] [PubMed] [Google Scholar]
- PRESCOTT D. M. The nuclear dependence of RNA synthesis in Acanthamoeba sp. Exp Cell Res. 1960 Feb;19:29–34. doi: 10.1016/0014-4827(60)90034-3. [DOI] [PubMed] [Google Scholar]
- Perry R. P. THE CELLULAR SITES OF SYNTHESIS OF RIBOSOMAL AND 4S RNA. Proc Natl Acad Sci U S A. 1962 Dec;48(12):2179–2186. doi: 10.1073/pnas.48.12.2179. [DOI] [PMC free article] [PubMed] [Google Scholar]
- REYNOLDS E. S. The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J Cell Biol. 1963 Apr;17:208–212. doi: 10.1083/jcb.17.1.208. [DOI] [PMC free article] [PubMed] [Google Scholar]
- SCHERRER K., LATHAM H., DARNELL J. E. Demonstration of an unstable RNA and of a precursor to ribosomal RNA in HeLa cells. Proc Natl Acad Sci U S A. 1963 Feb 15;49:240–248. doi: 10.1073/pnas.49.2.240. [DOI] [PMC free article] [PubMed] [Google Scholar]
- STEVENS B. J. THE EFFECT OF ACTINOMYCIN D ON NUCLEOLAR AND NUCLEAR FINE STRUCTURE IN THE SALIVARY GLAND CELL OF HIRONOMUS THUMMI. J Ultrastruct Res. 1964 Oct;11:329–353. doi: 10.1016/s0022-5320(64)90037-1. [DOI] [PubMed] [Google Scholar]
- WATSON M. Observations on a granule associated with chromatin in the nuclei of cells of rat and mouse. J Cell Biol. 1962 Apr;13:162–167. doi: 10.1083/jcb.13.1.162. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wiener J., Spiro D., Loewenstein W. R. Ultrastructure and permeability of nuclear membranes. J Cell Biol. 1965 Oct;27(1):107–117. doi: 10.1083/jcb.27.1.107. [DOI] [PMC free article] [PubMed] [Google Scholar]