scholarly journals Inhibition of vimentin synthesis and disruption of intermediate filaments in simian virus 40-infected monkey kidney cells.

1984 ◽  
Vol 4 (9) ◽  
pp. 1880-1889 ◽  
Author(s):  
A Ben-Ze'ev

The organization, synthesis, and phosphorylation of vimentin were studied at various times after infection of monkey kidney cells with simian virus 40. Late after infection (between 36 and 48 h postinfection) there is a dramatic reduction in vimentin synthesis that is paralleled by a specific disruption of the intermediate filament network. At the same time there is no apparent alteration of the organization or the synthesis of the actin-containing filaments and of the microtubules. The inhibition of vimentin synthesis is also reflected by the level of vimentin mRNA activity in the infected cells, as assayed in a cell-free in vitro translation system, and vimentin mRNA concentration as revealed by RNA blot hybridization to cloned vimentin cDNA. The level of vimentin phosphorylation also decreases dramatically but at a much earlier time after infection (between 14 and 24 h postinfection), when mitosis in the infected cells is blocked. Although the decrease in vimentin synthesis in simian virus 40-infected cells is paralleled by the alterations in the organization of the intermediate filament network, the phosphorylation of vimentin correlates with the cell cycle, as it does in other systems. A possible feedback control mechanism of vimentin synthesis by alterations in the organization of the intermediate filament network is discussed.

1984 ◽  
Vol 4 (9) ◽  
pp. 1880-1889
Author(s):  
A Ben-Ze'ev

The organization, synthesis, and phosphorylation of vimentin were studied at various times after infection of monkey kidney cells with simian virus 40. Late after infection (between 36 and 48 h postinfection) there is a dramatic reduction in vimentin synthesis that is paralleled by a specific disruption of the intermediate filament network. At the same time there is no apparent alteration of the organization or the synthesis of the actin-containing filaments and of the microtubules. The inhibition of vimentin synthesis is also reflected by the level of vimentin mRNA activity in the infected cells, as assayed in a cell-free in vitro translation system, and vimentin mRNA concentration as revealed by RNA blot hybridization to cloned vimentin cDNA. The level of vimentin phosphorylation also decreases dramatically but at a much earlier time after infection (between 14 and 24 h postinfection), when mitosis in the infected cells is blocked. Although the decrease in vimentin synthesis in simian virus 40-infected cells is paralleled by the alterations in the organization of the intermediate filament network, the phosphorylation of vimentin correlates with the cell cycle, as it does in other systems. A possible feedback control mechanism of vimentin synthesis by alterations in the organization of the intermediate filament network is discussed.


1985 ◽  
Vol 5 (6) ◽  
pp. 1490-1497 ◽  
Author(s):  
P Stuart ◽  
M Ito ◽  
C Stewart ◽  
S E Conrad

The thymidine kinase (TK) gene has been isolated from human genomic DNA. The gene was passaged twice by transfection of LTK- cells with human chromosomal DNA, and genomic libraries were made in lambda Charon 30 from a second-round TK+ transformant. When the library was screened with a human Alu probe, seven overlapping lambda clones from the human TK locus were obtained. None of the seven contained a functional TK gene as judged by transfection analysis, but several combinations of clones gave rise to TK+ colonies when cotransfected into TK- cells. A functional cDNA clone encoding the human TK gene has also been isolated. Using this cDNA clone as a probe in restriction enzyme/blot hybridization analyses, we have mapped the coding sequences and direction of transcription of the gene. We have also used a single-copy subclone from within the coding region to monitor steady-state levels of TK mRNA in serum-stimulated and simian virus 40-infected simian CV1 tissue culture cells. Our results indicate that the previously reported increase in TK enzyme levels seen after either treatment is paralleled by an equivalent increase in the steady-state levels of TK mRNA. In the case of simian virus 40-infected cells, the induction was delayed by 8 to 12 h, which is the length of time after infection required for early viral protein synthesis. In both cases, induction of TK mRNA coincides with the onset of DNA synthesis, but virally infected cells ultimately accumulate more TK mRNA than do serum-stimulated cells.


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