Nucleic Acid Synthesis in Relation to the Cell Division Cycle*

Taylor, J. Herbert

doi:10.1111/j.1749-6632.1960.tb23259.x

Cited by 265 publications

(113 citation statements)

References 9 publications

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“…During mitosis, transcription by RNA polymerase II (and probably also pre-mRNA-processing events) is repressed (34,40). The fate of pre-existing hnRNAs within these complexes is not known.…”

Section: Discussionmentioning

confidence: 99%

Cell cycle-regulated phosphorylation of the pre-mRNA-binding (heterogeneous nuclear ribonucleoprotein) C proteins.

Piñol-Roma¹,

Dreyfuss²

1993

Mol. Cell. Biol.

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Heterogeneous nuclear ribonucleoprotein (hnRNP) complexes, the structures that contain heterogeneous nuclear RNA and its associated proteins, constitute one of the most abundant components of the eukaryotic nucleus. hnRNPs appear to play important roles in the processing, and possibly also in the transport, of mRNA. hnRNP C proteins (Cl, Mr of 41,000; C2, Mr of 43,000 [by sodium dodecyl sulfate-polyacrylamide gel electrophoresis]) are among the most abundant pre-mRNA-binding proteins, and they bind tenaciously to sequences relevant to pre-mRNA processing, including the polypyrimidine stretch of introns (when it is uridine rich). C proteins are found in the nucleus during the interphase, but during mitosis they disperse throughout the cell. They have been shown previously to be phosphorylated in vivo, and they can be phosphorylated in vitro by a casein kinase type II. We have identified and partially purified at least two additional C protein kinases. One of these, termed Cs kinase, caused a distinct mobility shift of C proteins on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These phosphorylated C proteins, the Cs proteins, were the prevalent forms of C proteins during mitosis, and Cs kinase activity was also increased in extracts prepared from mitotic cells. Thus, hnRNP C proteins undergo cell cycle-dependent phosphorylation by a cell cycle-regulated protein kinase. Cs kinase activity appears to be distinct from the well-characterized mitosis-specific histone Hi kinase activity. Several additional hnRNP proteins are also phosphorylated during mitosis and are thus also potential substrates for Cs kinase. These novel phosphorylations may be important in regulating the assembly and disassembly of hnRNP complexes and in the function or cellular localization of RNA-binding proteins.RNA polymerase II transcripts, collectively termed heterogeneous nuclear RNAs (hnRNAs), associate as they are transcribed in the nuclei of eukaryotic cells with a specific subset of proteins to form heterogeneous nuclear ribonucleoprotein (hnRNP) complexes (12, 15). In human HeLa cells, these complexes contain, in addition to hnRNA, an assortment of at least 20 different abundant polypeptides (7, 30). As this association persists throughout their nuclear residency, it is assumed that the ensuing events that pre-mRNAs undergo to become functional translatable cytoplasmic mRNAs occur on hnRNPs rather than on naked RNA molecules.Of the ca. 20 major hnRNP proteins identified, the C proteins have occupied much of the focus of hnRNP research for several reasons. They are a prominent doublet (Cl [41 kDa] and C2 [43 kDa]) in HeLa cells) of nuclear acidic proteins which remain bound to the RNA at salt concentrations at which most of the other hnRNPs dissociate (3, 7). C proteins can also be readily UV-cross-linked to poly(A)-containing nuclear RNA in vivo (13,14,42). Immunofluorescence microscopy with monoclonal antibodies in a variety of vertebrate cells has shown that C proteins are localized to the nucleoplasm and are excluded fro...

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Section: Discussionmentioning

confidence: 99%

Cell cycle-regulated phosphorylation of the pre-mRNA-binding (heterogeneous nuclear ribonucleoprotein) C proteins.

Piñol-Roma¹,

Dreyfuss²

1993

Mol. Cell. Biol.

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“…[42][43][44][45][46][47][48] This inhibition is intentional. Introns in pre-mRNA must be spliced out, before mRNA is translated in the cytoplasm.…”

Section: Mitotic Inhibition Of Transcriptionmentioning

confidence: 99%

“…Supporting this prediction, transcription is inhibited during mitosis. [42][43][44][45][46][47][48] As one of multiple mechanisms, the general transcription factor TFIID undergo mitosis-specific phosphorylation and is displaced from the disassembling prophase nucleus to the mitotic cytoplasm around the time of nuclear envelope breakdown. 46 …”

Section: Mitotic Inhibition Of Transcriptionmentioning

confidence: 99%

Mitotic Arrest and Cell Fate: Why and How Mitotic Inhibition of Transcription Drives Mutually Exclusive Events

2007

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“…Taylor (18) showed by radioautography that RNA synthesis is depressed in cells in mitosis, but he found normal incorporation of arginine into protein. More recent radioautographic evidence (12,14) suggests that both RNA synthesis and protein synthesis are inhibited during mitosis in mammalian cells.…”

Section: Introductionmentioning

confidence: 99%

Ribonucleic Acid and Protein Synthesis in Mitotic Hela Cells

Johnson

Holland

1965

The Journal of Cell Biology

109

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HcLa cells arrested in mitosis were obtained in large numbers, with only very slight interphase cell contamination, by employing the agitation method of Terasima and Tolmach, and Robbins and Marcus. Protein synthesis and RNA synthesis were almost completely supprcsscd in mitotic cells. Active polyribosomes were nearly absent in mitotic cells as compared with intcrphase cells treated in the same way. Cell-free protein synthesis and RNA polymcrase activity were also greatly depressed in extracts of metaphasc cells. The dcoxyribonuclcoprotein (DNP) of condenscd chromosomes from mitotic cells was less cfficicnt as a template for Escherichia coli RNA polymcrase than was DNP from interphase cells, although isolated DNA from both sources was equally active as a primer. Despite very poor endogenous amino acid incorporation by extracts of mctaphase cells, polyuridylate stimulated phenylalanine incorporation by a larger factor in mitotic cell extracts than it did in interphase cell cxtracts. These rcsults suggest that RNA synthesis is suppressed in mitotic cells because the condensed chromosomes cannot act as a template, and that protein synthesis is deprcsscd at least in part because messenger RNA becomes unavailable to ribosomes. This conclusion was supported by the demonstration that cells arrested in mctaphase supported multiplication of normal yields of poliovirus, thereby showing that the mitotic cell is capable of considerable synthesis of RNA and protein.

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Nucleic Acid Synthesis in Relation to the Cell Division Cycle*

Cited by 265 publications

References 9 publications

Cell cycle-regulated phosphorylation of the pre-mRNA-binding (heterogeneous nuclear ribonucleoprotein) C proteins.

Cell cycle-regulated phosphorylation of the pre-mRNA-binding (heterogeneous nuclear ribonucleoprotein) C proteins.

Mitotic Arrest and Cell Fate: Why and How Mitotic Inhibition of Transcription Drives Mutually Exclusive Events

Ribonucleic Acid and Protein Synthesis in Mitotic Hela Cells

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