Abstract
The process of expulsion of the nucleus during the transformation of the late erythroblast to reticulocyte is described. Erythroid clones taken from the spleen of lethally irradiated mice transplanted with syngeneic bone marrow were used. 10–12-day old isolated clones were fixed in glutaraldehyde, then in osmium tetroxide. Ultra-thin sections were stained with uranyl acetate and/or lead citrate before examination. Late (orthochromatic) erythroblasts develop pseudopod-like cytoplasmic protrusions into one of which the nucleus gradually penetrates, being deformed by the extrusion through the relatively narrow passage. During the whole process, mitochondria and vesicular and membranous elements are concentrated in the cytoplasm. Once outside the cell, the nucleus reassumes its rounded form. It is surrounded by a narrow rim of cytoplasm and structurally altered plasma membrane and is connected to the rest of the cell by a bridge. Elongated vacuoles appear within this bridge, with a resulting release of the enveloped nucleus which is soon phagocytized by macrophages; this leaves behind the newly formed reticulocyte. During this process, the cytoplasmic protrusions, the agglomeration of mitochondria, and the mode of separation of the nucleus from the rest of the cell are similar to those occurring in mitotic division.
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Selected References
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- ALBRECHT M. Studien zur Frage der Erythroblastenentkernung au Kulturen van Meerschweinchenknochenmark. Acta Haematol. 1951 Aug;6(2):83–91. doi: 10.1159/000203909. [DOI] [PubMed] [Google Scholar]
- BESSIS M., BRICKA M. Aspect dynamique des cellules du sang; son étude par la microcinématographie en contraste de phase. Rev Hematol. 1952;7(3):407–435. [PubMed] [Google Scholar]
- DAVIES H. G. Structure in nucleated erythrocytes. J Biophys Biochem Cytol. 1961 Mar;9:671–687. doi: 10.1083/jcb.9.3.671. [DOI] [PMC free article] [PubMed] [Google Scholar]
- GRASSO J. A., SWIFT H., ACKERMAN G. A. Observations on the development of erythrocytes in mammalian fetal liver. J Cell Biol. 1962 Aug;14:235–254. doi: 10.1083/jcb.14.2.235. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MUIR A. R., KERR D. N. Erythropoiesis: an electron microscopical study. Q J Exp Physiol Cogn Med Sci. 1958 Jan;43(1):106–114. doi: 10.1113/expphysiol.1958.sp001295. [DOI] [PubMed] [Google Scholar]
- Orlic D., Gordon A. S., Rhodin J. A. An ultrastructural study of erythropoietin-induced red cell formation in mouse spleen. J Ultrastruct Res. 1965 Dec;13(5):516–542. doi: 10.1016/s0022-5320(65)90012-2. [DOI] [PubMed] [Google Scholar]
- RIFKIND R. A., DANON D., MARKS P. A. ALTERATIONS IN POLYRIBOSOMES DURING ERYTHROID CELL MATURATION. J Cell Biol. 1964 Sep;22:599–611. doi: 10.1083/jcb.22.3.599. [DOI] [PMC free article] [PubMed] [Google Scholar]
- RYTER A., KELLENBERGER E. L'inclusion au polyester pour l'ultramicrotomie. J Ultrastruct Res. 1958 Dec;2(2):200–214. doi: 10.1016/s0022-5320(58)90018-2. [DOI] [PubMed] [Google Scholar]
- TILL J. E., McCULLOCH E. A. A direct measurement of the radiation sensitivity of normal mouse bone marrow cells. Radiat Res. 1961 Feb;14:213–222. [PubMed] [Google Scholar]
- Weiss L. The structure of bone marrow. Functional interrelationships of vascular and hematopoietic compartments in experimental hemolytic anemia: an electron microscopic study. J Morphol. 1965 Nov;117(3):467–537. doi: 10.1002/jmor.1051170308. [DOI] [PubMed] [Google Scholar]