Genetic determinants of growth phase-dependent and adenovirus 5-responsive expression of the Chinese hamster thymidine kinase gene are contained within thymidine kinase mRNA sequences.

Lewis, J A; Matkovich, D A

doi:10.1128/mcb.6.6.2262

Cited by 34 publications

(22 citation statements)

References 25 publications

(26 reference statements)

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“…3A), we conclude that promoter and regulatory DNA sequences are present within the clone. Similar results were reported for chicken, hamster, and human tk genes isolated (4,33,42), suggesting an evolutionarily conserved, close physical linkage between tk controlling and coding regions in different species. Our observation permitted us to use the cloned mouse sequences to identify regions important for tk gene expression.…”

Section: Methodssupporting

confidence: 76%

“…These results are in agreement with a recent report by Hofbauer et al (23), showing that expression of the mouse tk cDNA is dramatically reduced in cells arrested in the G1 phase of the cell cycle by sodium butyrate. Other groups have also found that hamster and human tk cDNAs contain sequences mediating increased TK enzyme activity in association with the entry of cells into the S phase of the cell cycle (33,55 Fig. 4H]).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Transcriptional and posttranscriptional mechanisms regulate murine thymidine kinase gene expression in serum-stimulated cells.

Lieberman¹,

Lin²,

Yeh³

et al. 1988

Mol. Cell. Biol.

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We previously isolated and characterized the structure of murine thymidine kinase (tk) genomic and cDNA sequences to begin a study designed to identify regions of the tk gene important for regulated expression during the transition of cells from Go to a proliferating state. In this report, we describe the stable transfection of the cloned gene into L-M(TK-) cells and show that both thymidine kinase (TK) enzyme activity and DNA synthesis increase in parallel when transfectants in Go arrest are stimulated by serum. To define promoter and regulatory regions more precisely, we have constructed a series of tk minigenes and have examined their expression in stable transfectants after serum stimulation. We have identified a 291-base-pair DNA fragment at the 5' end of the tk gene that has promoter function, and we have determined its sequence. In addition, we have found that DNA sequences which mediate serum-induced expression of TK are transcribed, since expression of the murine tk cDNA, fused to a promoter from either the murine tk gene, the simian virus 40 early region, or the herpes simplex virus tk gene, is stimulated by serum. Our constructs also reveal that the murine tk polyadenylation signal is not required for regulation, nor is most of the 3' untranslated region. RNA dot blot analysis indicates that murine cytoplasmic tk mRNA levels always parallel TK enzyme activity. Nuclear runon transcription assays show less than a 2-fold increase in transcription from the cloned tk gene in serumstimulated transfectants, but an 11-fold increase in mouse L929 cells, which are inherently TK+. These results taken together suggest that the murine tk gene is controlled in serum-stimulated cells by a transcriptional mechanism influenced by DNA sequences that flank tk and also by a posttranscriptional system linked to gene sequences that are transcribed.Thymidine kinase (TK; EC 2.7.1.21) participates in the salvage pathway for pyrimidine nucleotide biosynthesis, catalyzing the phosphorylation of thymidine (TdR) to form thymidine 5'-monophosphate. Two major versions of the enzyme have been characterized in mammalian cells; one is found in the cytoplasm, and the other is found in the mitochondria (8, 27). They are encoded by genes located on different autosomes (15,30,37,63), and although they catalyze the same basic phosphorylation reaction, the biochemical characteristics of each enzyme and of each reaction are unique (27). The cytosolic form of TK is of special interest, since its activity is regulated in association with several cellular metabolic activities and events. Enzyme activity is high in cells infected with certain oncogenic viruses (for a review, see reference 29), in many rapidly proliferating tumor cell populations (14), and in cells during passage through the S phase of the cell cycle (3, 35). In contrast, nonproliferating cells, including those that have terminally differentiated (42), and also cells that are not in the S phase (3, 35), express little or no TK activity.We previously described the cloning and phys...

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Section: Methodssupporting

confidence: 76%

Section: Methodsmentioning

confidence: 99%

Transcriptional and posttranscriptional mechanisms regulate murine thymidine kinase gene expression in serum-stimulated cells.

Lieberman¹,

Lin²,

Yeh³

et al. 1988

Mol. Cell. Biol.

View full text Add to dashboard Cite

show abstract

“…Like ODC, serum-induced changes in chicken [39] and mouse [40] TK mRNAs are smaller than changes in activity. Regulation of cytosolic TK in mouse L-MTK- [40] and rat-4 [41] cells has been shown, by methods similar to those reported here, to have components localized within the protein coding region. The mouse TK gene contains additional determinants outside the coding region that regulates an additional 4 to 5-fold change in mRNA levels.…”

Section: Odc Lability and Its Effect On Regulationmentioning

confidence: 56%

Regulation of mouse ornithine decarboxylase activity by cell growth, serum and tetradecanoyl phorbol acetate is governed primarily by sequences within the coding region of the gene

1989

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To determine the genetic elements required for modulation of ornithine decarboxylase (ODC) activity in response to cell growth or treatment with serum or with tetradecanoyl phorbol acetate, ODCdeficient cells were transfected with a series of recombinant DNAs encoding mouse ODC. All of the transfected cells expressing an intact mouse ODC protein displayed regulation of ODC activity, including those expressing a construct deprived of all ODC-specific sequence information except the protein-coding region. ODC mRNA changed much less than enzymatic activity. A mutation of the protein-coding region that converted ODC from an unstable to a stable intracellular protein attenuated the regulatory response. We conclude that post-transcriptional events associated with ODC degradation dominate the response to these stimuli.

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“…The situation has been further complicated by the fact that hybrid TK genes utilizing heterologous promoters are cell cycle regulated in several systems (13,16); this has led investigators to conclude that transcriptional control is not occurring. In fact, the presence of dual levels of control is now established for many of the S phase-regulated genes that have been examined.…”

Section: Resultsmentioning

confidence: 99%

Evidence for transcriptional and post-transcriptional control of the cellular thymidine kinase gene.

Stewart¹,

Ito²,

Conrad³

1987

Mol. Cell. Biol.

109

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We have studied the cell cycle-regulated expression of the thymidine kinase (TK) gene in mammalian tissue culture cells. TK mRNA and enzyme levels are low in resting, GO-phase cells, but increase dramatically (10-to 20-fold) during the S phase in both serum-stimulated and simian virus 40-infected cells. To determine whether an increase in the rate of TK gene transcription is responsible for this induction, nuclear run-on transcription assays were performed at various times after serum stimulation or simian virus 40 infection of growth-arrested simian CV1 cells. When assays were performed at 12-h intervals, a small (two-to threefold) but reproducible increase in TK transcription was detected during the S phase. When time points were chosen to span the G1-S interface a larger (six-to sevenfold) increase in transcriptional activity was observed in serum-stimulated cells but not in simian virus 40-infected cells. The large increase in TK mRNA levels and the relatively small increase in transcription rates in growth-stimulated cells suggest that TK gene expression is controlled at both a transcriptional and post-transcriptional level during the mammalian cell cycle. To identify the DNA sequences required for cell cycle-regulated expression, several TK cDNA clones were transfected into Rat-3 TK-cells, and their expression was examined in resting and serum-stimulated cultures. These experiments indicated that the body of the TK cDNA is sufficient to insure cell cycle-regulated expression regardless of the promoter or polyadenylation signal used.

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Genetic determinants of growth phase-dependent and adenovirus 5-responsive expression of the Chinese hamster thymidine kinase gene are contained within thymidine kinase mRNA sequences.

Cited by 34 publications

References 25 publications

Transcriptional and posttranscriptional mechanisms regulate murine thymidine kinase gene expression in serum-stimulated cells.

Transcriptional and posttranscriptional mechanisms regulate murine thymidine kinase gene expression in serum-stimulated cells.

Regulation of mouse ornithine decarboxylase activity by cell growth, serum and tetradecanoyl phorbol acetate is governed primarily by sequences within the coding region of the gene

Evidence for transcriptional and post-transcriptional control of the cellular thymidine kinase gene.

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