Abstract
Onion (Allium cepa) and bean (Vicia faba) root tip cells containing many micronuclei, derived from x-ray-induced chromosome fragments, were exposed to H3-thymidine and H3-cytidine to determine the ability of such fragments to undergo DNA and RNA synthesis. Only a few micronuclei in onion and many in bean roots synthesize nucleic acid simultaneously with their main nuclei. A few micronuclei labeled with H3-thymidine undergo mitotic chromosome condensation along with the main nuclei, while the unlabeled ones never do so. The onset of nucleic acid synthesis as well as mitosis in micronuclei appears to be under generalized cellular control. Although all chromosomes and chromosome fragments at telophase give a positive reaction for a silver stainable nucleolar fraction, in the subsequent interphase only some micronuclei, derived from such chromosome fragments, are found to maintain nucleoli; others lose them with time. Those micronuclei which maintain nucleoli, perhaps due to the presence of specific chromosomal regions, are also active in DNA and RNA synthesis. These results are compatible with the concept that nucleoli and associated chromosome regions play an important role in the primary biosynthetic processes of the cell.
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Selected References
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- CHEVREMONT M., BASSLEER R., BAECKELAND E. [New research on desoxyribonucleic acids in cooled, then reheated, cultures of fibroblasts. Cytophotometric and histoautoradiographic studies. Cytoplasmic localization of DNA]. Arch Biol (Liege) 1961;72:501–524. [PubMed] [Google Scholar]
- FEINENDEGEN L. E., BOND V. P., HUGHES W. L. RNA mediation in DNA synthesis in HeLa cells studied with tritium labeled cytidine and thymidine. Exp Cell Res. 1961 Dec;25:627–647. doi: 10.1016/0014-4827(61)90194-x. [DOI] [PubMed] [Google Scholar]
- FEINENDEGEN L. E., BOND V. P., SHREEVE W. W., PAINTER R. B. RNA and DNA metabolism in human tissue culture cells studied with tritiated cytidine. Exp Cell Res. 1960 Apr;19:443–459. doi: 10.1016/0014-4827(60)90054-9. [DOI] [PubMed] [Google Scholar]
- FITZGERALD P. J., VINIJCHAIKUL K. Nucleic acid metabolism of pancreatic cells as revealed by cytidine-H3 and thymidine-H3. Lab Invest. 1959 Jan-Feb;8(1):319–329. [PubMed] [Google Scholar]
- Gaulden M. E., Perry R. P. INFLUENCE OF THE NUCLEOLUS ON MITOSIS AS REVEALED BY ULTRAVIOLET MICROBEAM IRRADIATION. Proc Natl Acad Sci U S A. 1958 Jun;44(6):553–559. doi: 10.1073/pnas.44.6.553. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HOTTA Y., STERN H. Transient phosphorylation of deoxyribosides and regulation of deoxyribonucleic acid synthesis. J Biophys Biochem Cytol. 1961 Nov;11:311–319. doi: 10.1083/jcb.11.2.311. [DOI] [PMC free article] [PubMed] [Google Scholar]
- PELLING G. Chromosomal synthesis of ribonucleic acid as shown by incorporation of uridine labelled with tritium. Nature. 1959 Aug 22;184(Suppl 9):655–656. doi: 10.1038/184655a0. [DOI] [PubMed] [Google Scholar]
- RASCH E., WOODARD J. W. Basic proteins of plant nuclei during normal and pathological cell growth. J Biophys Biochem Cytol. 1959 Oct;6:263–276. doi: 10.1083/jcb.6.2.263. [DOI] [PMC free article] [PubMed] [Google Scholar]
- RHO J. H., BONNER J. The site of ribonucleic acid synthesis in the isolated nucleus. Proc Natl Acad Sci U S A. 1961 Oct 15;47:1611–1619. doi: 10.1073/pnas.47.10.1611. [DOI] [PMC free article] [PubMed] [Google Scholar]
- SEED J. Inhibition of nucleic acid synthesis caused by x-irradiation of the nucleolus. Proc R Soc Lond B Biol Sci. 1960 Jun 14;152:387–396. doi: 10.1098/rspb.1960.0046. [DOI] [PubMed] [Google Scholar]
- TAYLOR J. H. Asynchronous duplication of chromosomes in cultured cells of Chinese hamster. J Biophys Biochem Cytol. 1960 Jun;7:455–464. doi: 10.1083/jcb.7.3.455. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WIMBER D. E. Asynchronous replication of deoxyribonucleic acid in root tip chromosomes of Tradescantia paludosa. Exp Cell Res. 1961 Mar;23:402–407. doi: 10.1016/0014-4827(61)90048-9. [DOI] [PubMed] [Google Scholar]
- WOODARD J., RASCH E., SWIFT H. Nucleic acid and protein metabolism during the mitotic cycle in Vicia faba. J Biophys Biochem Cytol. 1961 Feb;9:445–462. doi: 10.1083/jcb.9.2.445. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WOODS P. S., TAYLOR J. H. Studies of ribonucleic acid metabolism with tritium-labeled cytidine. Lab Invest. 1959 Jan-Feb;8(1):309–318. [PubMed] [Google Scholar]