Studies on synchronous division of tissue culture cells initiated by excess thymidine

Bootsma, D.; Budke, L.; Vos, O.

doi:10.1016/s0014-4827(64)81035-1

Cited by 329 publications

(92 citation statements)

References 10 publications

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“…The cells were synchronized at the G 1 /S transition by a double-thymidine block with 2.5 mM thymidine (Bootsma et al, 1964). The cells were then released to proceed through mitosis.…”

Section: Cell Culturementioning

confidence: 99%

Partially Processed pre-rRNA Is Preserved in Association with Processing Components in Nucleolus-derived Foci during Mitosis

Dundr

Olson

1998

MBoC

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Previous studies showed that components implicated in pre-rRNA processing, including U3 small nucleolar (sno)RNA, fibrillarin, nucleolin, and proteins B23 and p52, accumulate in perichromosomal regions and in numerous mitotic cytoplasmic particles, termed nucleolus-derived foci (NDF) between early anaphase and late telophase. The latter structures were analyzed for the presence of pre-rRNA by fluorescence in situ hybridization using probes for segments of pre-rRNA with known half-lives. The NDF did not contain the short-lived 5Ј-external transcribed spacer (ETS) leader segment upstream from the primary processing site in 47S pre-rRNA. However, the NDF contained sequences from the 5Ј-ETS core, 18S, internal transcribed spacer 1 (ITS1), and 28S segments and also had detectable, but significantly reduced, levels of the 3Ј-ETS sequence. Northern analyses showed that in mitotic cells, the latter sequences were present predominantly in 45S-46S pre-rRNAs, indicating that high-molecular weight processing intermediates are preserved during mitosis. Two additional essential processing components were also found in the NDF: U8 snoRNA and hPop1 (a protein component of RNase MRP and RNase P). Thus, the NDF appear to be large complexes containing partially processed pre-rRNA associated with processing components in which processing has been significantly suppressed. The NDF may facilitate coordinated assembly of postmitotic nucleoli. INTRODUCTIONThe nucleolus is a prominent membraneless subnuclear compartment assembled around clusters of tandemly repeated rDNA genes from which prerRNA is transcribed and subsequently folded, processed, modified, and assembled into small and large ribosomal subunits (Scheer et al., 1993;Shaw and Jordan, 1995;Maden and Hughes, 1997). A remarkable aspect of the cell cycle is the disintegration of the nucleolus during mitosis and its reassembly as the daughter cells proceed toward G 1 phase. A pivotal event in this process is the repression of RNA polymerase (pol) I-driven pre-rRNA synthesis between prophase and telophase (Prescott and Bender, 1962). At the same time, nucleolar components disperse to various subcellular locations as the maternal nucleoli diassemble (Goessens, 1984).A comprehensive understanding of the locations and fates of nucleolar components during mitosis is slowly emerging (Scheer et al., 1993;Hernandez-Verdun and Gautier, 1994). For example, much of the RNA pol I transcription machinery and DNA topoisomerase I remain associated with the nucleolus organizer regions (NORs) 1 of chromosomes between nucleolar disassembly in late prophase and reassembly in telophase (Scheer et al., 1993; Weisenberger and * Corresponding author. 1 Abbrevations used: DFC, dense fibrillar component; ETS, external transcribed spacer; GC, granular component; ITS, internal transcribed spacer; NDF, nucleolus-derived foci; NOR, nucleolus organizer region; PNB, prenucleolar body; pol, polymerase; snoRNA, small nucleolar RNA; sno-RNP, small nucleolar ribonucleoprotein.© 1998 by The American Society for Ce...

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“…The cells were synchronized at the G 1 /S transition by a double-thymidine block with 2.5 mM thymidine (Bootsma et al, 1964). The cells were then released to proceed through mitosis.…”

Section: Cell Culturementioning

confidence: 99%

Partially Processed pre-rRNA Is Preserved in Association with Processing Components in Nucleolus-derived Foci during Mitosis

Dundr

Olson

1998

MBoC

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“…Synchronization of the cells was carried out at 37'C in a warm room, either by selective detachment of mitotic cells (20,36) or by two cycles of 2 mm thymidine block (2,37) . Cells in the mitotic, G1, S, and G2 phases of cell cycle were obtained by blocking randomly growing cultures with 2 mm thymidine for 12 hr, releasing the cells into fresh, thymidine-free Eagle's Minimal Essential Medium (MEM) (10), and plating in 1 liter Blake bottles .…”

Section: Cells and Synchronizationmentioning

confidence: 99%

THE SYNTHESIS OF ACIDIC CHROMOSOMAL PROTEINS DURING THE CELL CYCLE OF HELA S-3 CELLS

Stein

Borun

1972

The Journal of Cell Biology

270

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The synthesis and accumulation of acidic proteins in the tightly bound residual nuclear fraction goes on throughout the cell cycle of continuously dividing populations of HeLa S-3 cells ; however, during late GI there is an increased rate of synthesis and accumulation of these proteins which precedes the onset of DNA synthesis . Unlike that of the histones, whose synthesis is tightly coupled to DNA replication, the synthesis of acidic residual nuclear proteins is insensitive to inhibitors of DNA synthesis . Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of acidic residual nuclear proteins shows different profiles during the G I , S, and G 2 phases of the cell cycle . These results suggest that, in contrast to histones whose synthesis appears to be highly regulated, the acidic residual proteins may have a regulatory function in the control of cell proliferation in continuously dividing mammalian cells .

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“…If cells are synchronized with aminopterin (Kishimoto & Lieberman, 1965) or excess of thymidine (Bootsma, Budke & Vos, 1964) then in the S phase and the G2 phase there is little change in activity of the nuclear preparation with native DNA as primer. Over this period the nuclear fraction shows greater activity when denatured DNA is used as primer and there is a small increase in this activity during the S phase.…”

mentioning

confidence: 99%

Changes in activity of nuclear deoxyribonucleic acid polymerase in synchronized mouse cells

Adams

Lindsay

1969

Biochemical Journal

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Studies on synchronous division of tissue culture cells initiated by excess thymidine

Cited by 329 publications

References 10 publications

Partially Processed pre-rRNA Is Preserved in Association with Processing Components in Nucleolus-derived Foci during Mitosis

Partially Processed pre-rRNA Is Preserved in Association with Processing Components in Nucleolus-derived Foci during Mitosis

THE SYNTHESIS OF ACIDIC CHROMOSOMAL PROTEINS DURING THE CELL CYCLE OF HELA S-3 CELLS

Changes in activity of nuclear deoxyribonucleic acid polymerase in synchronized mouse cells

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