Previous Article | Next Article ![]()
Mol. Cell. Biol., 06 1997, 3254-3260, Vol 17, No. 6
R Banholzer, AP Nair, HH Hirsch, XF Ming and C Moroni
We analyzed the effect of rapamycin on autocrine mast cell tumor lines with
abnormally stable interleukin-3 (IL-3) transcripts due to a defect in mRNA
degradation. Rapamycin inhibited IL-3 mRNA expression specifically, while
transcripts of IL-4 and IL-6 were not affected. As indicated by the use of
the transcriptional inhibitor actinomycin D or by reporter constructs,
inhibition was posttranscriptional and resulted from destabilization of the
mRNA. Transcripts from transgenes lacking the AU-rich 3' untranslated
region were refractory to drug-induced degradation, suggesting that these
3' sequences contain the target of the rapamycin effect. Rapamycin did not
promote IL-3 mRNA degradation in cells of a tumor variant lacking
expression of FKBP12, the binding protein of rapamycin. Experiments with
wortmannin indicated that rapamycin does not act via p70S6 kinase. FK-506,
another ligand of FKBP12 affecting the phosphatase calcineurin, did not
antagonize but shared the effect of rapamycin. Our data fit a model whereby
both FKBP12 and calcineurin target an unknown regulator of IL-3 mRNA
turnover.
Copyright © 1997, American Society for Microbiology
Rapamycin destabilizes interleukin-3 mRNA in autocrine tumor cells by a mechanism requiring an intact 3' untranslated region
Institute for Medical Microbiology, University of Basel, Switzerland.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»