Abstract
The term pore complex is proposed for approximately cylindrical formations which are observed with the electron microscope to penetrate the nuclear envelope of cells. Cross-sections of the pore complex are somewhat annular in shape, but differ in appearance depending upon the level of the cross-section with respect to the nuclear surface. An explanation is offered for the apparent discrepancy between the width of pores in sections perpendicular to the nuclear envelope and the width of cross-sections of the pore complex in tangential sections. Channels associated with the pore complex extend deep into the nucleus. Although crescents and spirals of ribonucleoprotein particles were often seen in the immediate vicinity of the outer nuclear membrane, direct association with the pore complex was not observed. Many examples were found of pores that were not covered by a continuous membrane although the possibility of such a covering in some cases is not precluded.
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Selected References
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- 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]
- GALL J. G. Observations on the nuclear membrane with the electron microscope. Exp Cell Res. 1954 Aug;7(1):197–200. doi: 10.1016/0014-4827(54)90054-3. [DOI] [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]
- GLAUERT A. M., GLAUERT R. H. Araldite as an embedding medium for electron microscopy. J Biophys Biochem Cytol. 1958 Mar 25;4(2):191–194. doi: 10.1083/jcb.4.2.191. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KUFF E. L., HOGEBOOM G. H., DALTON A. J. Centrifugal, biochemical, and electron microscopic analysis of cytoplasmic particulates in liver homogenates. J Biophys Biochem Cytol. 1956 Jan 25;2(1):33–54. [PMC free article] [PubMed] [Google Scholar]
- MOSES M. J. Studies on nuclei using correlated cytochemical, light, and electron microscope techniques. J Biophys Biochem Cytol. 1956 Jul 25;2(4 Suppl):397–406. doi: 10.1083/jcb.2.4.397. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MOSES M. J. The relation between the axial complex of meiotic prophase chromosomes and chromosome pairing in a salamander (Plethodon cinereus). J Biophys Biochem Cytol. 1958 Sep 25;4(5):633–638. doi: 10.1083/jcb.4.5.633. [DOI] [PMC free article] [PubMed] [Google Scholar]
- PALADE G. E. A small particulate component of the cytoplasm. J Biophys Biochem Cytol. 1955 Jan;1(1):59–68. doi: 10.1083/jcb.1.1.59. [DOI] [PMC free article] [PubMed] [Google Scholar]
- PALADE G. E. A small particulate component of the cytoplasm. J Biophys Biochem Cytol. 1955 Jan;1(1):59–68. doi: 10.1083/jcb.1.1.59. [DOI] [PMC free article] [PubMed] [Google Scholar]
- PALADE G. E., SIEKEVITZ P. Liver microsomes; an integrated morphological and biochemical study. J Biophys Biochem Cytol. 1956 Mar 25;2(2):171–200. doi: 10.1083/jcb.2.2.171. [DOI] [PMC free article] [PubMed] [Google Scholar]
- PALADE G. E., SIEKEVITZ P. Pancreatic microsomes; an integrated morphological and biochemical study. J Biophys Biochem Cytol. 1956 Nov 25;2(6):671–690. doi: 10.1083/jcb.2.6.671. [DOI] [PMC free article] [PubMed] [Google Scholar]
- PEACHEY L. D. Thin sections. I. A study of section thickness and physical distortion produced during microtomy. J Biophys Biochem Cytol. 1958 May 25;4(3):233–242. doi: 10.1083/jcb.4.3.233. [DOI] [PMC free article] [PubMed] [Google Scholar]
- RUTHMANN A. Basophilic lamellar systems in the crayfish spermatocyte. J Biophys Biochem Cytol. 1958 May 25;4(3):267–274. doi: 10.1083/jcb.4.3.267. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WATSON M. L. Reduction of heating artifacts in thin sections examined in the electron microscope. J Biophys Biochem Cytol. 1957 Nov 25;3(6):1017–1022. doi: 10.1083/jcb.3.6.1017. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WATSON M. L. Staining of tissue sections for electron microscopy with heavy metals. II. Application of solutions containing lead and barium. J Biophys Biochem Cytol. 1958 Nov 25;4(6):727–730. doi: 10.1083/jcb.4.6.727. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WATSON M. L. Staining of tissue sections for electron microscopy with heavy metals. J Biophys Biochem Cytol. 1958 Jul 25;4(4):475–478. doi: 10.1083/jcb.4.4.475. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WISCHNITZER S. An electron microscope study of the nuclear envelope of amphibian oocytes. J Ultrastruct Res. 1958 Apr;1(3):201–222. doi: 10.1016/s0022-5320(58)80001-5. [DOI] [PubMed] [Google Scholar]