Elevation of large-T antigen production by sodium butyrate treatment of SV40-transformed WI-38 fibroblasts.
The effects of sodium butyrate on simian virus 40 early gene expression were determined in SV40-transformed human embryonic lung fibroblasts (SVWI-38). Northern blot analysis and nuclear run-off transcription studies revealed that treatment of cells with millimolar concentrations of sodium butyrate (2.5 to 10 mM) resulted in increased levels of SV40 early gene transcripts, with a concomitant increase in their corresponding proteins (large-T and small-t antigens). Although sodium butyrate treatment enhanced the expression of the early genes, it was associated with a reduction in cell growth and total protein synthesis, as measured by cell number and incorporation of 3H-leucine into macromolecules, respectively. Immunoprecipitation of 35S-labelled cellular proteins with anti-p53 and anti-T antibodies revealed that the level of the cellular protein, p53, declined markedly in the presence of sodium butyrate. Furthermore, in control cells only 30% of the p53 was complexed with large-T antigen, whereas in butyrate-treated cells all the p53 was complexed with large-T antigen. The increased early gene expression was not due to altered methylation patterns, gene amplification, or rearrangement of the integrated SV40 genome. Sodium butyrate treatment did, however, result in the appearance of a new nuclear protein which bound specifically to a SV40 promoter fragment containing large-T antigen binding sites I and II.
Goldberg
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YP
MRC/UCT Research Unit for the Cell Biology of Atherosclerosis, Department of Medical Biochemistry, University of Cape Town Medical School, Observatory, South Africa.
Leaner
V D
VD
Parker
M I
MI
D000952:Antigens, Polyomavirus Transforming / Q000096:biosynthesis*; D015139:Blotting, Southern; D002087:Butyrates / Q000494:pharmacology*; D020148:Butyric Acid; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D004279:DNA, Viral / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D006801:Humans; D008745:Methylation; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000096:biosynthesis; D012367:RNA, Viral / Q000096:biosynthesis; D013539:Simian virus 40 / Q000187:drug effects* / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis
D000952:Antigens, Polyomavirus Transforming; D002087:Butyrates; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D012367:RNA, Viral; D016159:Tumor Suppressor Protein p53; D020148:Butyric Acid